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The treatment landscape of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) has significantly evolved in recent years. Targeted therapy with Bruton’s tyrosine kinase (BTK) inhibitors and BCL-2 inhibitors has emerged as an effective chemotherapy-free option for patients with previously untreated or relapsed/refractory CLL/SLL. Undetectable minimal residual disease after the end of treatment is emerging as an important predictor of progression-free and overall survival for patients treated with fixed-duration BCL-2 inhibitor-based treatment. These NCCN Guidelines Insights discuss the updates to the NCCN Guidelines for CLL/SLL specific to the use of chemotherapy-free treatment options for patients with treatment-naïve and relapsed/refractory disease.

Flow cytometric analysis of NK, NK T cell and Treg subpopulations.

Supplemental figure legends

Gating strategy for analysis of live lymphocytes.

Plasma cytokine levels of LTCR responders compared to all other patients.

Purpose:Rituximab and lenalidomide are effective for previously untreated and relapsed/refractory (R/R) indolent non-Hodgkin lymphoma (iNHL). However, long-term survival and predictive biomarkers are not well described.Patients and Methods:We conducted two phase II open-label trials involving 60 patients with previously untreated and R/R advanced-stage iNHL. Patients received lenalidomide and rituximab induction followed by continuous lenalidomide until disease progression or unacceptable toxicity. The primary endpoint was overall response rate (ORR). Correlative studies included plasma cytokine monitoring, flow cytometry of peripheral blood mononuclear cells (PBMC; days 0, 15, 30, and 60), and RNA sequencing (RNA-seq) of pretreatment tumor biopsies.Results:At a median follow-up of 63 months for previously untreated and 100 months for R/R, ORR was 82% for both. The 11 R/R patients who achieved complete remission remained in continuous remission for 16 to 141 months, thereafter. Median overall survival (OS) was not reached in the previously untreated and was 140 months (95% confidence interval, 53.4–140) in the R/R group. A mixed-effects linear regression model identified significant associations between Granzyme B+ (GranB+) CD8+ T cells and long-term complete response (LTCR; P = 5.3e-4). Furthermore, prior to start of therapy, treatment response could be predicted by B-cell and GranB+ CD8+ T-cell levels (% total lymphocytes).Conclusions:Rituximab plus lenalidomide followed by continuous lenalidomide is effective with manageable toxicity in patients with previously untreated and R/R iNHL. This regimen produces durable remissions, even in heavily pretreated patients, with some lasting greater than 10 years. GranB+ CD8+ T cells, B cells, and plasma IFNγ allowed prediction of LTCR but need validation in larger trials.

Purpose: Rituximab and lenalidomide are effective for previously untreated and relapsed/refractory (R/R) indolent non-Hodgkin lymphoma (iNHL). However, long-term survival and predictive biomarkers are not well described. Patients and Methods: We conducted two phase II open-label trials involving 60 patients with previously untreated and R/R advanced-stage iNHL. Patients received lenalidomide and rituximab induction followed by continuous lenalidomide until disease progression or unacceptable toxicity. The primary endpoint was overall response rate (ORR). Correlative studies included plasma cytokine monitoring, flow cytometry of peripheral blood mononuclear cells (PBMC; days 0, 15, 30, and 60), and RNA sequencing (RNA-seq) of pretreatment tumor biopsies. Results: At a median follow-up of 63 months for previously untreated and 100 months for R/R, ORR was 82% for both. The 11 R/R patients who achieved complete remission remained in continuous remission for 16 to 141 months, thereafter. Median overall survival (OS) was not reached in the previously untreated and was 140 months (95% confidence interval, 53.4–140) in the R/R group. A mixed-effects linear regression model identified significant associations between Granzyme B+ (GranB+) CD8+ T cells and long-term complete response (LTCR; P = 5.3e-4). Furthermore, prior to start of therapy, treatment response could be predicted by B-cell and GranB+ CD8+ T-cell levels (% total lymphocytes). Conclusions: Rituximab plus lenalidomide followed by continuous lenalidomide is effective with manageable toxicity in patients with previously untreated and R/R iNHL. This regimen produces durable remissions, even in heavily pretreated patients, with some lasting greater than 10 years. GranB+ CD8+ T cells, B cells, and plasma IFNγ allowed prediction of LTCR but need validation in larger trials.

Alisertib, an Aurora kinase A inhibitor, was evaluated in a Phase 1 study in combination with the histone deacetylase inhibitor vorinostat, in patients with relapsed/refractory lymphoid malignancies (N=34; ). Patients received alisertib plus vorinostat in 21-day treatment cycles with escalating doses of alisertib following a continuous or an intermittent schedule. All dose-limiting toxicities (DLTs) were hematologic and there were no study-related deaths. The recommended phase 2 dose (RP2D) of the combination was 20 mg bid of alisertib and 200 mg bid of vorinostat on the intermittent schedule. A 13-patient expansion cohort was treated for a total of 18 patients at the RP2D. There were no DLTs at the RP2D, and toxicities were mainly hematologic. Two patients with DLBCL achieved a durable complete response, and two patients with HL achieved partial response. Alisertib plus vorinostat showed encouraging clinical activity with a manageable safety profile in heavily pretreated patients with advanced disease.

Background Clarithromycin (CL) is a macrolide antibiotic with anti-MM activity when combined with dexamethasone (dex), and imids. Immunomodulatory activity and altered dex metabolism are proposed mechanisms of CL activity, though concerns over toxicity remain. We designed a phase I/II study of pomalidomide (pom), ixazomib (ix), CL and dex (PICd) to assess the tolerability and efficacy of CL in RRMM. Methods The primary endpoints were the maximal tolerated and recommended phase 2 dose of PICd. Secondary endpoints were overall response rate (ORR)(≥ PR), disease control rate (DCR)(≥ SD), duration of response (DOR) and progression free (PFS) and overall survival (OS). Cycles were 28 days. CL 250 mg PO BID was given c1 d15-21 and d1-21 subsequently. Pom 4 mg PO daily for 21 days, ix 4 mg d1, 8, 15 and dex 40 mg (20 mg if age >75 years) d1, 8, 15 and 22 were given for 6 cycles. After C6, maintenance until unacceptable toxicity or PD consisted of reduced pom, ix, dex and CL doses at 2, 2.3, 20 and 250 mg respectively. CL was held during weeks 1-2 of cycle 1 to facilitate correlative studies. Results A total of 32 patients consented to study. Of these, 4 were unevaluable for response/survival due to rapid disease progression (n=2), late screen failure (n=1), and withdrawn consent (n=1). Of these, 3 were included in toxicity data. Median follow up was 20 months (mo). Median age was 68.5 (range 54 – 82), 74% were male. Median number of prior therapies was 2 (1 – 5). All patients had prior lenalidomide and proteasome inhibitor exposure. Of the 26 patients with FISH data, 15 (57%) had high risk cytogenetics. Of these, 9 (35%) had del(17p), 10 (38%) had + 1q and 2 (8%) had t(4;14). Four had del(17p) and +1q; 1 each had t(4;14) and del(17p) or +1q. At least 1 grade 3-4 adverse event (AE) was experienced by 17 (55%) patients. Grade 3-4 hematologic AEs were seen in 8 (26%), of which 5 (16%) had neutropenia. Ten (31%) experienced grade 3-4 non-hematologic AEs, of which infections were the most common [4 (13%) patients]. Grade 3-4 neuropathy was not seen. ORR was 75%, DCR was 100%; 13 patients (56%) achieved ≥VGPR while 4 (14%) achieved CR/sCR. High risk cytogenetics were not associated with ORR (Fisher exact test P=1) or ≥VGPR rates (Fisher exact test P=0.42). Median DOR was 23.2 mo (95% Confidence interval: 12.2 – not reached); median PFS was 24.7 mo (13.4 – NR). There was no difference in median PFS in patients with or without del(17p): 24.7 mo (7.5 – NR) vs 22.2 mo (11.0 – NR) respectively (log rank P=0.4). Patients with + 1q had a median PFS of 13.4 mo (11 – NR) vs to 39.6 mo (25 – NR) in those without +1q (log rank P=0.09). Median OS was 37.3 mo (21.5 – NR). Correlative studies examining immune effector subsets before and after the addition of CL will be presented at the meeting. Conclusions Overall, PICd is a promising all PO regimen which combines convenient administration, tolerable side effect profile, and long duration of disease control.

Background: While many humanized monoclonal antibodies utilize complement-dependent cytotoxicity, the complement depleting effects of these antibodies and the impact of complement replacement on treatment response are not well-described. Methods: We conducted a phase 2 trial involving patients with relapsed/refractory chronic lymphocytic leukemia (CLL). Patients were treated with ofatumumab with fresh frozen plasma (FFP) used as a source of complement replacement. The primary endpoint was objective response rate. Correlative endpoints included complement levels (C3 and C4) and complement activity (CH50) which was drawn at baseline and after ofatumumab with FFP administration. Results: Among 12 enrolled patients, overall response rate was 83% with two patients (17%) achieving a complete response. While only two (17%) patients had low complement activity at baseline, eight (67%) developed low levels of complement activity after ofatumumab treatment with FFP replacement. The magnitude of complement depletion did not correlate with response. Adverse events were minimal. The combination of ofatumumab and FFP demonstrated tolerability and surprising activity in high-risk CLL patients. Conclusions: The combination of ofatumumab and FFP demonstrated tolerability and surprising activity in high-risk CLL patients. Complement replacement should be studied further as a minimally toxic approach to improve efficacy of monoclonal antibody-based regimens. J Hematol. 2020;9(3):79-83 doi: https://doi.org/10.14740/jh721

Background: While many humanized monoclonal antibodies utilize complement dependent cytotoxicity, the complement depleting effects of these antibodies and the effect of complement replacement are not well-described. This study sought to examine complement levels and the effect of complement repletion after treatment with ofatumumab in patients with chronic lymphocytic leukemia (CLL). Methods: Twelve patients with relapsed or refractory CLL were treated with ofatumumab in combination with fresh frozen plasma used as complement replacement. The primary endpoint was objective response rate. Correlative endpoints included complement levels C3 and C4 and complement activity. Results: Adverse events were minimal, and efficacy was encouraging with an overall response rate of 83% and 2 patients (17%) achieving a complete response. While only 2 (17%) of patients had low complement activity at baseline, 8 (67%) developed low levels of complement activity. At a median follow-up time of 37 months the median progression-free survival was 12.5 months. Conclusions: While a minority of patients had low complement activity at baseline, a majority developed low levels of complement with ofatumumab treatment. The magnitude of complement depletion did not correlate with response. Future trials are needed to further explore complement replacement as a less toxic strategy to improve efficacy of monoclonal antibody-based regimens in CLL.

Background Ponatinib, a third-generation BCR-ABL1 tyrosine kinase inhibitor (TKI), + hyper-CVAD showed remarkable activity against Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL), and may be superior to chemotherapy + earlier generation TKIs in terms of depth of remission, event-free survival (EFS), and overall survival (OS). However, this regimen's efficacy and tolerability have yet to be externally validated. Here, we summarize our real-world experience with ponatinib + hyper-CVAD for untreated Ph+ ALL and other Ph+ acute or blast phase leukemias. Methods We retrospectively analyzed all adults treated at the University of California, Davis (UCD) from March 2012 to May 2021 with ponatinib + hyper-CVAD upfront. The primary endpoints were 3-year OS and EFS. Secondary endpoints were complete molecular response (CMR), measurable residual disease (MRD) negativity by multiparameter flow cytometry (MFC), complete cytogenetic response (CCyR) rates, and adverse events (AEs). Time to event analyses were done via the Kaplan-Meier method. Patients alive were censored at their last follow-up date. Patients undergoing allogeneic hematopoietic cell transplant (HCT) after 6 months of achieving complete remission (CR) were censored at the time of HCT for the landmark analysis. Patients with missing data were excluded from the response analyses. Results We identified 13 Ph+ ALL patients who received ponatinib + hyper-CVAD for initial induction. The baseline characteristics for the Ph+ ALL patients are summarized in Table 1. The median follow-up was 16 months. The median number of hyper-CVAD cycles completed was 8 (range, 1-8) with ponatinib. Two patients proceeded to HCT in CR1, one at 3.5 months after starting induction, and due to difficulty controlling the patient's concurrent multiple myeloma prior to HCT and recovery from anti-neoplastic therapy, the second was delayed to 46 months after starting induction. The 3-year OS and EFS with ponatinib + hyper-CVAD were each 92% (95% confidence interval, 78.9-100) (Figure 1). Landmark analysis completed 6 months following CR showed a 3-year OS of 100% in patients treated with ponatinib + hyper-CVAD without HCT in first CR (CR1). The CMR, CCyR, and MRD-negativity by MFC rates with ponatinib were all 92.3% (12/13). The median time to CMR, CCyR, and MRD-negativity by MFC were 51 days, 22 days, and 53 days, respectively. Notable AEs with ponatinib include neutropenic fever (92%), bacterial infection (69%), transaminitis (38%), venous thromboembolism (31%), invasive fungal infection (15%), hemorrhage (15%), cerebrovascular accident (CVA) (15%), and tumor lysis syndrome (8%). One patient died during induction with ponatinib due to a bacterial infection. Two patients switched to a different TKI due to a CVA after 4 and 24 months. Only 2 patients did not complete 8 cycles of hyper-CVAD, due to death during induction (n=1) and proceeding to HCT after 3 cycles (n=1). As for similar Ph+ leukemias, 3 chronic myeloid leukemia with lymphoid blast crisis (CML-LBC), 1 CML with mixed phenotype blast crisis (CML-MPBC), and 1 with mixed phenotype acute leukemia (MPAL) were treated with ponatinib + hyper-CVAD. The MPAL patient achieved CMR within 55 days, while the CML-MPBC and 2 CML-LBC patients achieved CMR after HCT. The third CML-LBC patient is in CR with ongoing treatment. After median follow-up of 25 months, all 5 were alive, and only the MPAL patient relapsed 28 months after starting treatment and 1 year after HCT. Conclusion To our knowledge, this is the first report externally validating the efficacy and tolerability of ponatinib + hyper-CVAD for Ph+ ALL. We also show the feasibility of using this regimen in patients with Ph+ CML-LBC, CML-MPBC and MPAL. Despite the small sample size and retrospective nature, our study supports existing data demonstrating that this regimen challenges both the designation of Ph+ ALL as a high-risk disease and the trend to transplant in CR1. Our findings support that ponatinib + hyper-CVAD should be considered a standard of care for Ph+ ALL. Figure 1 Figure 1. Disclosures Kaesberg: Incyte: Speakers Bureau. Rosenberg: Takeda, Janssen: Speakers Bureau. Abedi: BMS/Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Speakers Bureau; Seattle Genetics: Speakers Bureau. Tuscano: Genentech, Pharamcyclics, Abbvie, BMS, Acrotech, Seattle Genetics, Takeda: Research Funding. Jonas: AbbVie, BMS, Genentech, GlycoMimetics, Jazz, Pfizer, Takeda, Treadwell: Consultancy; 47, AbbVie, Accelerated Medical Diagnostics, Amgen, AROG, Celgene, Daiichi Sankyo, F. Hoffmann-La Roche, Forma, Genentech/Roche, Gilead, GlycoMimetics, Hanmi, Immune-Onc, Incyte, Jazz, Loxo Oncology, Pfizer, Pharmacyclics, Sigma Tau, Treadwell: Research Funding; AbbVie: Other: Travel reimbursement. OffLabel Disclosure: Ponatinib is approved for Philadelphia chromosome positive acute lymphoblastic leukemia (Ph+ALL) that is resistant or intolerant to prior tyrosine kinase inhibitor therapy. In this study, we described outcomes with ponatinib in combination with hyperCVAD in the frontline setting, which is off-label.

Context Little is known about the hopes patients with advanced (incurable) cancer have for their treatment. Objectives The objective of this study was to describe the treatment hopes of advanced cancer patients, factors associated with expressing specific hopes, and the persons with whom hopes are discussed. Methods We surveyed 265 advanced cancer patients in the U.S. about their hopes for treatment at the baseline and after three months. We developed a taxonomy of hopes for treatment, which two investigators used to independently code patient responses. We explored associations between hopes for cure and patient covariates. Results We developed eight categories of hopes. We were able to apply these codes reliably, and 95% of the patient's responses fit at least one hope category. The hope categories in order of descending baseline prevalence were as follows: quality of life, life extension, tumor stabilization, remission, milestone, unqualified cure, control not otherwise specified, and cure tempered by realism. Most patients reported discussing hopes with partners, family/friends, and oncologists; a minority reported discussing hopes with nurses, primary care physicians, clergy, or support groups. In logistic regression analysis, unqualified hopes for cure were more likely in younger patients and in those who did not endorse discussing their hopes with primary care physicians. Conclusion Advanced cancer patients harbor a range of treatment hopes. These hopes often are not discussed with key members of the health care team. Younger age and lack of discussion of hopes with primary care physicians may lead to less realistic hopes for cure.

Importance Observational studies demonstrate links between patient-centered communication, quality of life (QOL), and aggressive treatments in advanced cancer, yet few randomized clinical trials (RCTs) of communication interventions have been reported. Objective To determine whether a combined intervention involving oncologists, patients with advanced cancer, and caregivers would promote patient-centered communication, and to estimate intervention effects on shared understanding, patient-physician relationships, QOL, and aggressive treatments in the last 30 days of life. Design, setting, and participants Cluster RCT at community- and hospital-based cancer clinics in Western New York and Northern California; 38 medical oncologists (mean age 44.6 years; 11 (29%) female) and 265 community-dwelling adult patients with advanced nonhematologic cancer participated (mean age, 64.4 years, 146 [55.0%] female, 235 [89%] white; enrolled August 2012 to June 2014; followed for 3 years); 194 patients had participating caregivers. Interventions Oncologists received individualized communication training using standardized patient instructors while patients received question prompt lists and individualized communication coaching to identify issues to address during an upcoming oncologist visit. Both interventions focused on engaging patients in consultations, responding to emotions, informing patients about prognosis and treatment choices, and balanced framing of information. Control participants received no training. Main outcomes and measures The prespecified primary outcome was a composite measure of patient-centered communication coded from audio recordings of the first oncologist visit following patient coaching (intervention group) or enrollment (control). Secondary outcomes included the patient-physician relationship, shared understanding of prognosis, QOL, and aggressive treatments and hospice use in the last 30 days of life. Results Data from 38 oncologists (19 randomized to intervention) and 265 patients (130 intervention) were analyzed. In fully adjusted models, the intervention resulted in clinically and statistically significant improvements in the primary physician-patient communication end point (adjusted intervention effect, 0.34; 95% CI, 0.06-0.62; P = .02). Differences in secondary outcomes were not statistically significant. Conclusions and relevance A combined intervention that included oncologist communication training and coaching for patients with advanced cancer was effective in improving patient-centered communication but did not affect secondary outcomes. Trial registration clinicaltrials.gov Identifier: NCT01485627.

Background: As a single agent, rituximab produces an overall response rate (ORR) of 20-50% in patients with relapsed/refractory (r/r) B-cell non-Hodgkin lymphomas (NHL). Acquired resistance occurs, however, partially due to defective host immune effector mechanisms. Efforts to augment immune function have included combining rituximab with immune modulators such as IL-2, IL-12, interferonand lenalidomide. These efforts have resulted in improved efficacy of rituximab. Ipilimumab is a human IgG1κ monoclonal antibody (mAb) specific for the cytotoxic T lymphocyte-associated antigen-4 (CTLA-4, CD152) expressed on activated T cells. CTLA-4 is a negative regulator of T-cell responses. Ipilimumab augments the immune response by disrupting the interaction of CTLA-4 with its ligands, B7-1 (CD80) and B7-2 (CD86). We therefore hypothesize that ipilimumab will augment the efficacy of rituximab. This phase I with an expansion cohort was designed to assess the safety of this combined therapy. Methods: Patients ≥ 18 years old with r/r CD20+ NHL, measurable disease, KPS ≥ 70%, neutrophils ≥ 1000, platelets ≥ 50,000 and adequate kidney and liver function were eligible. In this phase I with an expansion cohort, after establishing the recommended Phase II dose (RP2D), study patients would be randomized to differing treatment schedules of rituximab and ipilimumab. For induction in phase I, rituximab was given every week for four weeks and ipilimumab was administered every 3 weeks for 4 doses. Primary endpoints included toxicity and determination of the maximum tolerated dose (MTD)/RP2D during the first 7 weeks of induction of ipilimumab (2 doses) when given in combination with rituximab (4 doses, 375mg/m2 per dose). Secondary end points included immune response, ORR and progression free survival (PFS). In the phase I component, a standard 3+3 design was used to determine the MTD/RP2D. After the RP2D was established, 20 more patients would be randomized to one of two schedules: Arm A - ipilimumab on Day 1 together with the first dose of rituximab, or Arm B - ipilimumab on Day 15 together with the third rituximab dose. After induction in both the Phase I and the expansion cohorts, ipilimumab and rituximab were given every 12 weeks (+/- 1 week) on the same day for 1 year. Results: As of August 1 2015, 21 patients have been enrolled (1SLL, 9FL, 6DLCL, 1MCL, 4 indeterminate): 15 are evaluable for toxicity assessment at 7 weeks. The median age was 62 (32-71) and the median number of prior regimens was 2 (1-6). The RP2D of ipilimumab when given with rituximab (375 mg/m2) was 3 mg/kg, which was the highest dose tested. The most common grade 1-2 AEs (>20%) were:anemia (33%); diarrhea (20%); constipation (27%); nausea/vomiting (33%); fatigue (40%); anorexia (33%); low albumin (53%); hypocalcemia (33%); hyponatremia (27%). The most common grade 3-4 AEs (≥ 5%) were: anemia (20%); diarrhea (13%); leukopenia (13%); and hyponatremia (27%). There were no study related deaths. Twelve patients remain on treatment, 6 came off due to progression, 2 due to toxicity, and there was one death (unrelated). Conclusion: The RP2D of ipilimumab when given in combination with rituximab is 3 mg/kg. This dose is safe and moderately well tolerated. Enrollment continues in the expansion cohort to assess efficacy and the ability of ipilimumab to augment the rituximab-mediated immune response. Disclosures Off Label Use: Ipilimumab to augment rituxan in treating lymphoma. Chen:Merck: Consultancy, Research Funding; genentech: Consultancy, Speakers Bureau; Millennium: Consultancy, Research Funding, Speakers Bureau; Seattle Genetics: Consultancy, Research Funding, Speakers Bureau.

Flockhouse virus (FHV) is a member of the nodavirus group of positive-strand RNA viruses. In the absence of additional compounds, a template-dependent RNA-dependent RNA polymerase extracted from FHV-infected cells synthesizes complementary (-)-strand copies of added FHV RNA to yield a double-stranded RNA product. Upon addition of glycerophospholipid (GPL), this system reproducibly carries out complete highly active replication of added FHV RNA, producing newly synthesized (+)-strand RNA in predominantly single-stranded RNA form. This accounts for previously observed effects of Lipofectin (a mixture of GPL and cationic lipid) in the system. All tested neutral and negatively charged GPLs except phosphatidic acid support complete FHV RNA replication in this in vitro system, as do phospholipid extracts from uninfected and FHV-infected cells. Neither sphingomyelin, a membrane phospholipid that is not derived from glycerol, nor cholesterol supported FHV RNA replication. Testing of compounds derived from GPL shows that the ability of active GPL to support FHV (+)-strand RNA synthesis is dependent on the structures of both the head group and the acyl chains. Neither the phosphorylated head group nor the diacylglycerol lipid moiety alone supports RNA replication. The length and saturation of acyl chains strongly influence the ability of GPL to support RNA replication. Other characteristics of this in vitro RNA replication system and the possible role played by membranes and their components in FHV RNA replication are discussed.

Newly synthesized virions of flock house virus (FHV), an insect nodavirus, were detected in plant cells inoculated with FHV RNA. FHV was found in whole plants of barley (Hordeum vulgare), cowpea (Vigna sinensis), chenopodium (Chenopodium hybridum), tobacco (Nicotiana tabacum), and Nicotiana benthamiana and in protoplasts derived from barley leaves. Virions produced in plants contained newly synthesized RNA as well as newly synthesized capsid protein. These results show that the intracellular environment in these plants is suitable for synthesis of a virus normally indigenous only to insects. Such synthesis involves, minimally, translation of viral RNA, RNA replication, and virion assembly. Inoculation of barley protoplasts with FHV virions resulted in synthesis of small amounts of progeny virions, suggesting that FHV virions are capable of releasing their RNA in plant cells. In N. benthamiana, virions resulting from inoculation with RNA were detected not only in inoculated leaves but also in other leaves of inoculated plants, suggesting that virions could move in this plant species. Such movement probably occurs by a passive transport through the vascular system rather than by an active transport involving mechanisms that have evolved for plant viruses.

Cell-free extracts of Drosophila melanogaster cells infected with FHV (Flockhouse virus) have the capacity to synthesize FHV RNA. When such extracts are incubated appropriately, ss and ds FHV RNA 1, -2, and -3 can be detected as synthesis products. Pulse-chase analyses indicate that radioactivity, incorporated into ds RNA 1, -2, and -3 is chased into ss RNA 1, -2, and -3, suggesting that these ds RNAs are intermediates in FHV RNA replication. When the cell-free extracts are treated with detergents to solubilize cellular membranes, only ds RNA 1, -2, and -3 can be detected as synthesis products. The cell-free extracts, treated with a ribonuclease to remove endogenous templates, have the capacity to replicate FHV RNA 1 and -2 when these RNAs are provided as templates, together with lipofectin. Both as and ds RNA 1 and -2 are detected as synthesis products. When RNA3 is provided as a template, only ds RNA3 is synthesized. In the absence of lipofectin or in the presence of detergent, only ds RNAs are detected as synthesis products and all the incorporated radioactivity is found in the strand complementary to that of the template. Our results are consistent with a mechanism in which second-strand synthesis, although not complementary strand synthesis, requires intact membranes. They also suggest that ds RNA3 is an intermediate in the synthesis of ss RNA3.

The genomic RNA2s of nodaviruses encode a single gene, that of protein alpha, the precursor of virion proteins beta and gamma. We compared the sequences of the RNA2s of the nodaviruses, black beetle virus (BBV), flock house virus, boolarra virus and nodamura virus, with the objective of identifying homologies in the primary and secondary structure of these RNAs and in the structure of their encoded protein. The sequences of the four RNAs were found to be similar, so that homologous regions relating to translation and RNA replication were readily identified. However, the overall, secondary structures in solution, deduced from calculations of optimal Watson-Crick base-pairing configurations, were very different for the four RNAs. We conclude that a particular, overall, secondary structure in solution within host cells is not required for virus viability. The partially refined X-ray structure of BBV (R = 26.4% for the current model) was used as a framework for comparing the structure of the encoded proteins of the four viruses. Mapping of the four protein sequences onto the BBV capsid showed many amino acid differences on the outer surface, indicating that the exteriors of the four virions are substantially different. Mapping in the beta-barrel region showed an intermediate level of differences, indicating that some freedom in choice of amino acid residues is possible there although the basic framework of the capsids is evidently conserved. Mapping onto the interior surface of the BBV capsid showed a high degree of conservation of amino acid residues, particularly near the protein cleavage site, implying that that region is nearly identical in all four virions and has an essential role in virion maturation, and also suggests that all four capsid interior surfaces have similar surfaces exposed to the viral RNA. Apart from a small portion of the C promoter, the amino terminus of the BBV protein (residues 1 to 60) is crystallographically disordered and the amino acid residues in that region are not well conserved. The disordered portion of the BBV protein clearly projects from the capsid inner surface into the interior of the virion, the region occupied by the viral RNA. In all four viruses, residues 1 to 60 had a high proportion of basic residues, suggesting a virus-specific interaction of the amino terminus with the virion RNA.

The greatest risk factor for cancer is aging. Human cancer incidence increases exponentially with advancing age. Cancer growth rate and potential for metastatic spread may be influenced by age-specific change in host response. Because cancer and aging are, thus, inextricably linked, the American Cancer Society should encourage submission of research proposals that address the mechanisms of aging and how aging alters cancer development.

Although brome mosaic virus RNA3 has only one translatable cistron, it can bind two 80S ribosomes at initiation. One ribosome binds at the first AUG codon (base 92-94). The other binds nearer the 5' end at an entry or holding site. Disome formation is thus unrelated to a silent cistron approximately 1,000 bases downstream.

We have adapted the chain-termination method for determining the nucleotide sequence of DNA of Sanger, Nicklen, and Coulson [(1977) Proc. Natl. Acad. Sci. USA 74, 5463--5467] for use with reverse transcriptase (RNA-directed DNA nucleotidyltransferase) on RNA templates. With this method and using a primer (the octanucleotide pdT7rC) directed at the 3'-terminal poly(A), we have determined a sequence of 166 residues in the genomic RNA of the picornavirus encephalomyocarditis virus.

Turnip crinkle virions contain genomic RNA, Mr approximately 1.4 x 10(6), small RNA, Mr approximately 1.5 x 10(5) and a heterogeneous collection of intermediate size. Turnip crinkle virion RNA was translated in rabbit reticulocyte lysates into three major unrelated products of molecular weight 38,000 (p38, the virion coat protein), 36,000 (p36), and 25,000 (p25). The same three products, but in different proportion, were synthesized in wheat embryo extracts. Certain intermediate size RNA fractions translated into p38 and p36 products much more efficiently than did unfractionated RNA. The 1.5 x 10(5) molecular weight RNA did not induce amino acid incorporation. We propose a translation map of the TCV genome, based on tryptic analyses of the major products and of putative read-through proteins.

RNA isolated from southern bean mosaic virions contains, in small amount, a subgenomic RNA (molecular weight, 0.38 × 10 6 ) that serves in vitro as an mRNA for southern bean mosaic virus coat protein. The RNA has a 5′-linked protein indistinguishable from the protein linked to the 5′ end of full-length genomic RNA. Its base sequence, determined to 91 bases from the 3′ end, is identical to the 3′-terminal sequence of the genomic RNA. The results suggest that the coat protein messenger sequence exists as a “silent” cistron near the 3′ end of the genomic RNA.

The amino acid sequence of BMV (brome mosaic virus) coat protein is presented and compared with the sequence derived from RNA structure. Apart from removal of the N-terminal methionine residue and acetylation of the following serine residue, no post-translational modifications occur.

Genetic recombination of DNA is one of the fundamental mechanisms underlying the evolution of DNA-based organisms and results in their diversity and adaptability. The importance of the role of recombination is far less evident for the RNA-based genomes that occur in most plant viruses and in many animal viruses. RNA recombination has been shown to promote the evolutionary variation of picornaviruses1–4, it is involved in the creation of defective interfering (DI) RNAs of positive- and negative-strand viruses5–9 and is implicated in the synthesis of the messenger RNAs of influenza virus10 and coronavirus11. However, RNA recombination has not been found to date in viruses that infect plants. In fact, the lack of DI RNAs and the inability to demonstrate recombination in mixedly infected plants has been regarded as evidence that plants do not support recombination of viral RNAs. Here we provide the first molecular evidence for recombination of plant viral RNA. For brome mosaic virus (BMV), a plus-stranded, tripartite-genome virus of monocots, we show that a deletion in the 3′ end region of a single BMV RNA genomic component can be repaired during the development of infection by recombination with the homologous region of either of the two remaining wild-type BMV RNA components. This result clearly shows that plant viruses have available powerful recombinatory mechanisms that previously were thought to exist only in animal hosts, thus they are able to adapt and diversify in a manner comparable to animal viruses. Moreover, our observation suggests an increased versatility of viruses for use as vectors in introducing new genes into plants.

The genomic RNA sequence of the cowpea strain of southern bean mosaic virus (SBMV-C) has been determined. The genome is 4194 nucleotides in length and has four open reading frames. A 5' proximal open frame, from base 49 to base 603, corresponds to the length of the P4 proteins translated in cell-free extracts from full-length and smaller virion RNA. The largest open frame extends from base 570 to base 3437 and encodes the two largest proteins translated in cell-free extracts from full-length virion RNA. Segments of this open reading frame's predicted amino acid sequence resemble those of known viral RNA polymerases, ATP-binding proteins, and viral genome-linked proteins. A third open frame extends from base 1895 to base 2380 and has not been correlated with an in vitro translation product. The fourth open reading frame is located in the 3' terminal region of the genome extending from base 3217 to base 4053. This frame encodes the SBMV capsid protein which is translated from subgenomic, virion RNA.

The black beetle virus (BBV) is an isometric insect virus whose genome consists of two messenger-active RNA molecules encapsidated in a single virion. The nucleotide sequence of BBV RNA1 (3105 bases) has been determined, and this, together with the sequence of BBV RNA2 (1399 bases) provides the complete primary structure of the BBV genome. The RNA1 sequence encompasses a 5' non-coding region of 38 nucleotides, a coding region for a protein of predicted molecular weight 101,873 (protein A, implicated in viral RNA synthesis) and a 3' proximal region encoding RNA3 (389 bases), a subgenomic messenger RNA made in infected cells but not encapsidated into virions. The RNA3 sequence starts 16 bases inside the coding region of protein A and contains two overlapping open reading frames for proteins of molecular weight 10,760 and 11,633, one of which is believed to be protein B, made in BBV-infected cells. A limited homology exists between the sequences of RNA1 and RNA2. Sequence regions have been identified that provide energetically favorable bonding between RNA2 and RNA1 possibly to facilitate their common encapsidation, and between RNA2 and negative strand RNA1 possibly to regulate the production of RNA3.

RNA transcripts of cloned cDNA of the genomic RNAs of BBV (black beetle virus) are infectious to cultured cells of Drosophila melanogaster. Individual transcripts had approximately 10% of the infectivity of the corresponding authentic virion RNA. Progeny virus resulting from transcript infection was phenotypically indistinguishable from the progenitor virus used to generate the original cDNA forms as judged by sucrose density gradient sedimentation, specific infectivity, plaque morphology, and serology. Although the transcript RNAs used to produce this virus had 20 nonviral bases headed by a capping group at their 5' termini, these 20 bases were absent in the progeny viral RNAs. The cDNA forms, and therefore the resulting transcript RNAs, should be readily modifiable by the techniques of recombinant DNA technology both for viral studies and for the insertion of foreign genes into the viral genome and thus into the host cytoplasm.

Rapid, detailed, and accurate analysis of the length spectrum of 3' terminal poly(A) in an RNA population can be obtained by 3'-terminal 32P-labelling of RNA with T4 RNA ligase, digestion with ribonucleases T1 and A, and use of gel sequencing methods. Length distributions of 3'-terminal poly(A) of EMC virus, poliovirus, rhinovirus, RAV-61, and CPMV virion RNAs as well as mouse globin mRNA are presented.

All four components of brome mosaic virus RNA have m 7 G 5′ ppp 5′ Gp as their 5′ terminus. The m 7 G can be removed by β-elimination, resulting in the conversion to pppGp.

Nuclease digestion of SBMV RNA releases a protein of molecular weight approximately 12,000 in addition to the four mononucleotides. The lack of reactivity of SBMV RNA to polynucleotide kinase and the absence of a capping group suggest that the protein is covalently attached to the 5' end of the RNA. RNA sequencing shows that the 3' terminus of SBMV RNA is not polyadenylated.

The plant viruses alfalfa mosaic virus (AMV) and brome mosaic virus (BMV) each divide their genetic information among three RNAs while tobacco mosaic virus (TMV) contains a single genomic RNA. Amino acid sequence comparisons suggest that the single proteins encoded by AMV RNA 1 and BMV RNA 1 and by AMV RNA 2 and BMV RNA 2 are related to the NH2-terminal two-thirds and the COOH-terminal one-third, respectively, of the largest protein encoded by TMV. Separating these two domains in the TMV RNA sequence is an amber termination codon, whose partial suppression allows translation of the downstream domain. Many of the residues that the TMV read-through domain and the segmented plant viruses have in common are also conserved in a read-through domain found in the nonstructural polyprotein of the animal alphaviruses Sindbis and Middelburg. We suggest that, despite substantial differences in gene organization and expression, all of these viruses use related proteins for common functions in RNA replication. Reassortment of functional modules of coding and regulatory sequence from preexisting viral or cellular sources, perhaps via RNA recombination, may be an important mechanism in RNA virus evolution.

Southern bean mosaic virus RNA was translated in wheat embryo extracts and in nuclease-treated rabbit reticulocyte lysates. Four principal products were synthesized: two related products with molecular weights of 105,000 and 75,000, a product with a molecular weight of 29,000 that closely resembled coat protein, and a product with a molecular weight of 14,000. Their proportion depended on ionic conditions and the translational system used.

A 3'-terminal oligonucleotide fragment, 161 bases long, can be obtained from each of the four brome mosaic virus RNAs by means of nuclease digestion. Like the four intact brome mosaic virus RNAs, each fragment accepts tyrosine in a reaction catalyzed by wheat germ aminoacyl-tRNA synthetase. The complete nucleotide sequence of the RNA 4 fragment has been determined by use of standard radiochemical methods. Comparative data for the fragments from RNAs 1, 2, and 3 show that they have nearly the same sequence as the RNA 4 fragment. The eight bases adjacent to the 3' terminus of the RNA 4 fragment are identical in sequence to the eight terminal bases of tyrosine tRNA from Torula utilis and eleven interior bases are identical in sequence to eleven bases encompassing the anticodon region of tyrosine tRNA from Saccharomyces cerevisiae, T. utilis, and Escherichia coli. Nevertheless, reasonable base-pairing schemes yield, at best, a distorted cloverleaf secondary structure.

The RNA from bacteriophage Qβ can be translated by cell-free extracts from wheat embryos. This translation, by 80 S ribosomes, occurs at a low magnesium ion concentration. Three products are synthesized which coelectrophorese with Qβ proteins synthesized in Escherichia coli extracts. The smallest of these has been identified as coat protein. Although the polycistronic bacteriophage message is translated with fidelity, the efficiency is much less than when the monocistronic brome mosaic virus coat protein message is translated.

Thrombospondin is a 420-kD platelet alpha-granule glycoprotein that binds specifically to heparin. We examined adhesion to thrombospondin of CHO K1 cells and three mutant CHO lines with varying deficiencies in glycosaminoglycan (GAG) synthesis. In an experiment in which the parent line (K1) had 78% adherence to thrombospondin adsorbed to tissue culture plastic, CHO S745 cells, with less than 6% normal GAG synthesis had 11% adherence. CHO S677 cells, with decreased heparan sulfate proteoglycan but increased chondroitin sulfate proteoglycan, had 42% adherence. CHO S803 cells, with decreased heparan sulfate proteoglycan and normal chondroitin sulfate proteoglycan, had 31% adherence. Heparin inhibited K1 cell adhesion to thrombospondin, but not fibronectin, in a concentration-dependent manner. Dermatan sulfate but not chondroitin sulfate was also inhibitory. There was markedly decreased K1 cell adhesion to a thrombospondin core fragment that lacked the heparin binding NH2-terminal domain. Purified heparin binding domain, although poorly adhesive when adsorbed to substratum, inhibited cell adhesion to intact thrombospondin. Adhesion was better for all cell lines tested, including three human tumor cell lines, when thrombospondin was adsorbed at pH 4.0 compared with pH 7.4. When adsorption of thrombospondin was done at pH 7.4, cell adhesion was better when thrombospondin was adsorbed in the presence of greater than or equal to 0.6 mM calcium, compared to 0.1 mM calcium or EDTA. These findings suggest that thrombospondin can adsorb to plastic with varying degrees of exposure of a cell adhesion domain. We conclude that the thrombospondin cell adhesion receptor on CHO cells is a heparan sulfate proteoglycan, and that cell adhesion to thrombospondin depends on conformation of adsorbed thrombospondin.

A cell-free protein synthesizing system was prepared from cells of Drosophila melanogaster line 1 and made mRNA dependent by treatment with micrococcal nuclease. The system was tested with homologous RNA from black beetle virus propagated in Drosophila cells, with Drosophila heat shock mRNA, and with various heterologous viral mRNA's. Under optimal conditions amino acid incorporation programmed with black beetle virus RNAs was 30-fold higher than endogenous incorporation. RNAs 1 and 2 primarily directed the synthesis of proteins with approximately molecular weights of 120,000 and 46,000, respectively. mRNA's, prepared by transcription from vesicular stomatitis virus or vaccinia virus, were translated efficiently and yielded products that comigrated with authentic viral proteins. Brome mosaic virus RNA and encephalomyocarditis virus RNA were translated poorly. The system retained full activity after freezing.

Group 4 phages TW19 and TW28 of Escherichia coli possess a “read-through” (IIb) protein, although group 2 phage GA does not. This may have implications concerning the evolution and classification of RNA phages.

The nucleotide sequence has been determined for the first 53 bases of brome mosaic virus RNA4, the monocistronic messenger for brome mosaic virus coat protein. The sequence includes the binding site for wheat embryo ribosomes. The 5′-terminal base is a modified guanosine attached to the penultimate base through a 5′ p-p-p 5′ link. The initiating AUG codon is only 10 nucleotides from the 5′-terminus. The 13 triplets following the AUG codon correspond to the known sequence of brome mosaic virus coat protein.

Crude lysates of black beetle virus (BBV)-infected cells of Drosophila melanogaster contain an RNA-dependent RNA polymerase activity not detectable in uninfected cells. The activity (designated BBV polymerase) sedimented at 20,000 × g , indicating an association with particulate material. It was solubilized from the pellet by sonication in a magnesium-deficient buffer. Differential centrifugation resulted in a 43-fold purification with 84% recovery of polymerase activity. The effects of divalent and monovalent cations, time, temperature, and pH on the activity of the partially purified polymerase were examined. RNA synthesis was not stimulated by the addition of exogenous BBV RNA, suggesting that an enzyme-template complex existed. Analysis of the RNA products of the RNA polymerase reaction indicated that full-length “negative” strand BBV RNAs were synthesized.

3' terminal fragments of BMV RNA as short as 153 bases in length serve as efficient templates in vitro for BMV-specific RNA polymerase. Template activity of such fragments or of native BMV RNA is abolished when cDNA fragments as short as 39 bases are hybridized to their 3' termini. Hybridization of cDNa fragments to regions of BMV RNA 200 or more bases distal to the 3' end has no discernible effect on initiation and little effect on elongation. We conclude that BMV RNA polymerase initiates binding with an RNA template through a mechanism mediated by the tRNA-like 3' end of BMV RNA, requiring at least some of the last 39, but no more than the last 153 bases.

When RNA from southern bean mosaic virus is fractionated on a sucrose gradient, the resulting absorbance profile shows a major peak corresponding to 1.4 × 10 6 MW together with a considerable amount of slower sedimenting material. The RNA from these gradient fractions was translated in wheat embryo extracts and reticulocyte lysates. Only RNA in the molecular weight range 0.3 – 0.4 × 10 6 was found to induce synthesis of coat protein (designated P3). RNA of molecular weight 1.4 × 10 6 induced synthesis of three proteins, P1, P2, and P4.

The 3' terminal 337 bases of BMV (brome mosaic virus) coat protein mRNA (BMV RNA4) are presented. This sequence includes the terminal portion of the coat protein cistron and the complete 300-base 3' noncoding sequence. The 3' noncoding sequence displays significant complementarity to the 5' terminal sequence of BMV RNA3 but not to the 5' terminal sequence of BMV RNA4.

The nucleotide sequence of black beetle virion (BBV) RNA2 has been determined. RNA2 is 1399 b long. Its 5' terminus is capped. Its 3' terminus has an unidentified moiety that renders the RNA resistent to polyadenylation and ligation. The first AUG codon at base 23 is followed by an open reading frame for a protein 407 amino acids long, the predicted size of coat protein precursor. A second open reading frame for a putative protein 72 amino acid residues long begins at base 1110. No other large open reading frames exist. The 5' half of the RNA can be folded into a long, imperfect hairpin of high predicted stability. The 3' half of the RNA can fold into a complex set of multiply bifurcated stem and loop regions.

Profound changes in the biology of cancer occur as people and experimental animals age. Many naturally occurring tumors in humans and experimental animals show slower growth with advancing age and longer host survival. The most likely cause for this alteration in tumor biology is the universal phenomenon of cellular immunesenescence. At the onset of sexual maturation, the thymus begins to involute. With this involution, a progressive decline is observed in T-cell functions, e.g., lymphokine production, response to mitogens, and response to antigenic stimulation. It has been proposed that the immune system plays an important role in the stimulation of tumor growth. This role in poorly antigenic tumors may overshadow the role of the immune system as a tumor suppressor. It has been shown that poorly antigenic murine tumors grow more slowly in immune deficient or aged mice. Human tumors are generally poorly antigenic and many (such as lung, breast, and colon carcinomas) also show decreased growth rates in older adults. This article describes age-related changes in the immune system and discusses the theories of immune enhancement of tumor growth. Consideration is also given to the explanation of increased incidence of cancer in elderly patients and the potential role of the immune system in this phenomenon.

AMV was purified by differential centrifugation and n -butanol chloroform-water extractions at 6°. Purified preparations exhibited three closely-spaced schlieren peaks in the analytical ultracentrifuge with sedimentation coefficients of 73, 89 and 99 S. The three fractions were partially separated from each other by the use of sucrose density-gradient techniques. Local-lesion assays demonstrated that infectivity was associated with the 99-S fraction. Precipitin endpoint, cross-absorption and gel-diffusion tests indicated that the three fractions were serologically similar. Electron micrographs showed that the particles were rod-like with diameters of 200 A and lengths 550 A or less. The 73-S fraction contained a greater proportion of particles shorter than 550 A than did the 99-S fraction. Approximately equal amounts of nucleic acid were associated with each of the three fractions. Attempts to show that the nucleic acid associated with the 73-S fraction was contributed by host organelles failed.