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The tumor microenvironment (TME) plays an important role in malignances as tumors react with a multitude of changes and microenvironmental cues. TME components modulate tumor profiles and treatment responses, thereby affecting sensitivity to anti-cancer agents. The limited clinical success of therapeutics, including immunotherapies, emphasizes an unmet need to identify new targets and develop preclinical platforms to accelerate anti-cancer drug discovery. Although in vitro methods are essential in early drug development, standard approaches, which do not capture the complexity of TME, have been historically favored for both discovery and evaluation of potential therapeutics. Resonant's IMPACT TME platform couples proprietary high-fidelity TME models with deep data-driven analytics for rapid and cost-effective discovery of novel targets and antibody-based therapeutics. Target and candidate selection is based upon a biology-forward approach driven by live animal immune systems and functional screening prior to target identification. Identified candidates are then prioritized via integration of publicly available information with internal functional and multi-omic data. Resultant targets display attributes, such as tumor selectivity and immune-modulatory capabilities, that are amenable to several therapeutic modalities, including antibody-drug conjugates (ADCs) and bispecifics. To date, Resonant has interrogated a variety of solid tumor types and thousands of candidates resulting in an expanding library of actionable antibodies and targets. Representative examples of in vitro and in vivo efficacy of selected candidates derived from the IMPACT TME platform are presented, highlighting their individual potential and validating the Resonant approach. As technological advances transform the landscape of therapeutics, the need for novel targets is burgeoning, and Resonant’s TME-driven platform provides a valuable tool to meet these demands. Citation Format: Polina R. Matre, Byung-Kwon Choi, Oliver Delgado, John K. Westwick. Novel in vitro TME platform for rapid cancer therapeutic and target discovery [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3440.

By phase contrast and scanning electron microscopy hairy cells were demonstrated in the peripheral blood, bone marrow and spleen of a patient with hairy cell leukemia. Immunofluorescent tests revealed IgD on the surface of 92 per cent, IgG, on 76 per cent, IgM on 12 per cent and albumin on 95 per cent of the cells from the spleen. After overnight culture, IgG and albumin were detected on 4 and 6 per cent of the cells respectively, while the number of IgD and IgM positive cells persisted. Fifty-two per cent of the hairy cells formed rosettes with erythrocytes sensitized with IgG antibodies (EA), whereas 70 per cent formed rosettes after trypsin and protease treatment. The hairy cells did not form rosettes with erythrocytes sensitized with IgM antibodies and complement (EAC), or with sheep and mouse erythrocytes. Cryostat sections of spleen strongly adsorbed EA, whereas no adsorption occurred with EAC or sheep erythrocytes. The hairy cells did not phagocytize latex particles or ingest a strain on yellow staphylococci. The results suggest that hairy cells from this patient probably were of B-lymphocyte origin.

Objective: As stress activates the inflammatory response system, and attempted suicide is connected with severe stress, we hypothesized that patients hospitalized for self-injurious behaviour have changed immunocompetence. Method: The concentration of immunoglobulins IgG, IgA, IgM, and the complement components C3 and C4 in 73 patients hospitalized for self-injurious behaviour was compared with those of 122 healthy controls. The immunoglobulins and complement were quantified by nephelometric technique. Results: The levels of IgG and IgM were significantly lower, and the complement C3 and C4 were significantly higher in self-injurious patients compared with controls. This was valid in both genders and the effects did not interact with gender. Conclusions: This controlled study showed that the concentrations of immunoglobulins were reduced and complement components were increased in patients who are admitted to hospital for self-injurious behaviour.

Background: Can plasmapheresis improve disease severity and lung function and reduce steroid doses in severe asthma patients dependent on oral corticosteroids? Methods: A pilot study with four asthma patients was undertaken using PEF (peak expiratory flow) symptom score, number of puffs of β2-agonist, and dose of systemic steroids as disease variables. After at least an 8-week run-in, the patients were randomized to a crossover treatment regimen consisting of either 10 days of plasmapheresis or placebo treatment. Each treatment was succeeded by an 8–26-week follow-up period. Results: No patients achieved a significant effect of plasmapheresis treatment according to the established criteria, nor did anyone experience deterioration. Conclusions: Removing humoral factors extensively over a 10-day period did not significantly influence the clinical condition of the four steroid-dependent asthma patients studied. Circulating humoral factors seem to be of little importance for the maintenance of the established chronic allergic inflammation in these patients. Plasmapheresis does not seem to be a treatment option for this patient category.

This study concerned the immunological correlates of stress and work. Self reported stress, emotional state, ego-strength, and defensiveness were examined in relation to measures of cellular immunity (T-cell response to Con A and number of T4 and T8 cells) and humoral immunity (concentrations of immunoglobulins and complement components in plasma) in a group of 96 Norwegian female bank employees. The analyses showed that workload, the stress factor with the highest group mean, was associated with number of T-cells, while strain due to body posture during work was related to concentrations of IgM and C3. Further, depression was significantly correlated with IgM concentration and T-cell number, and anxiety with C3 concentration. T-cell activity was the immunological parameter most consistently associated with psychological well-being, showing positive correlations with defensiveness and ego-strength and negative correlations with anxiety and depression. In conclusion, T-cell number and concentratio...

Using the ELISA technique to estimate serum antibodies against tetanus toxin, seven neonates with clinical tetanus were found to have antibody levels 4-13 times higher than the presumed minimum protective level of 0.01 IU/ml. All but one of their mothers had been vaccinated with tetanus toxoid in pregnancy. In two other neonates, whose mothers had received multiple booster doses of toxoid during pregnancy, the anti-toxin concentrations were 100- and 400-times the presumed protective level. Therefore the toxin dose may overwhelm the pre-existing anti-toxin level and produce disease. Furthermore, multiple booster injections of tetanus toxoid may not only enhance serum anti-toxin titres, but could also lead to an ineffective immune response.

As stress activates the inflammatory response system, and attempted suicide is connected with severe stress, we hypothesized that patients hospitalized for self-injurious behaviour have changed immunocompetence.The concentration of immunoglobulins IgG, IgA, IgM, and the complement components C3 and C4 in 73 patients hospitalized for self-injurious behaviour was compared with those of 122 healthy controls. The immunoglobulins and complement were quantified by nephelometric technique.The levels of IgG and IgM were significantly lower, and the complement C3 and C4 were significantly higher in self-injurious patients compared with controls. This was valid in both genders and the effects did not interact with gender.This controlled study showed that the concentrations of immunoglobulins were reduced and complement components were increased in patients who are admitted to hospital for self-injurious behaviour.

This study was conducted to investigate immunity to tetanus among pregnant women with verbal histories or documentation of having been vaccinated under the current five-dose tetanus toxoid (TT) schedule. It examined sera from 176 pregnant women attending antenatal care at Muhimbili Medical Centre in Dar es Salaam, Tanzania. Tetanus antitoxin level of 0.1 IU/ml was considered protective. Our findings show that 94.9% of women had tetanus antitoxinor = 0.1 IU/ml. Multivariate analysis revealed that time after last vaccination, TT doses received and TT vaccination status explained 7.5%, 5.7% and 2.3% of variations in tetanus antitoxin levels respectively. Pregnant women with non-protective levels of tetanus antitoxin (5.1%) pose great risks of neonatal tetanus to their newborns and are also susceptible to maternal tetanus. Proper keeping of TT vaccination records is vitally important to avoid hyper-immunisation.

Objective : To determine immunity to tetanus in male blood donors with previous diphtheriapertussis- tetanus (DPT)/tetanus toxoid (TT) vaccination. Design : A cross sectional study, conducted in September 1999. Setting : Blood bank, Muhimbili Medical Centre, Dar es Salaam, Tanzania. Methods : Using an antigen competition ELISA technique, serum tetanus anti-toxin levels in two hundred male blood donors were determined. Results : Vaccination history was absent in 43 (21.5%) blood donors, whereas 60 (30%) and 97 (48.5%) reported childhood DPT and TT vaccination, respectively. Tetanus anti-toxin was undetectable in 47 (23.5%) blood donors and the levels were below that considered protective (>>0.1 IU/ml) in 25 (12.5%). Among those with undetectable level, 43 (91.5%) had no vaccination history. Time after last DPT/TT vaccination correlated significantly with tetanus anti-toxin levels (r2=-0.331, p=0.001). In multivariate analysis, TT doses received and time after last vaccination explained 4.8% and 29.4%, respectively, of the variations in tetanus anti-toxin levels. Conclusion : Seventy two (36%) male blood donors were susceptible to tetanus and the susceptibility was highest from 48 years. A regular TT booster dose at 10 yearly intervals is recommended to provide adequate and long lasting immunity in male adults. Proper keeping of vaccination records is emphasised. (East African Medical Journal: 2002 79(2): 73-76)

Objectives: To determine, from laboratory records, the spectrum of bacterial and fungal pathogens isolated fromcerebrospinal fluids (CSF) of in-patients with meningitis at Muhimbili Medical Centre (MMC) in Dares Salaam and to ascertain the laboratory results (based on microscopy and culture) using the latex agglutination technique. Design: A retrospective study based on laboratory records of CSF samples investigated between November 1999 and June 2000 and a cross-sectional study involving investigation of 60 freshly collected CSF samples by conventional (microscopy and culture) and antigen detection by latex agglutination technique (LAT). Setting: Muhimbili Medical Centre in Dares Salaam, Tanzania. Investigations: Information from laboratory records, bacteriological examination of CSF by microscopy, culture and agglutination techniques. Result: According to records, a total of 1144 CSF samples were investigated between November 1999and June 2000, of which two hundred and twenty twospecimens (19.4%) had a positive bacterial or fungal culture. Fifty five of the isolates were from children (aged less than 15 years) and were; 20 (36.4%) were Streptococcus pneumoniae, 12(21.8%) were Cryptococcus neoformans, and nine (16.4%) were Haemophilus infIuenzae type b. The remaining 14 (25%) isolates included three group B streptococci, three Klebsiella spp, two E.coli, two Staphylococcus aureus, two Pseudomonas spp, one Moraxella and one Salmonella group B. For adults a total of 167 positive cultures were reported and 163 (97.6%) of the isolates were Cryptocaccus neoformans, two (1.2%) were Pseudomonas spp. and two were S. aureus. There was good agreement between conventional microscopy and culture with the latex agglutination technique in the identification of CSF pathogens. Conclusion: In children, S. pneumonia, and bacteria in general constituted the majority of isolates. Adult cases of meningitis were almost exclusively due to C. neoformans. Overall, C. neoformans appears to be the most common isolate among meningitis cases. Based on LAT results, our routine diagnostic methods seem to be adequate in the identification of the common CSF pathogens.

The authors aim was to determine tetanus immunity in women of childbearing age (15-44 years) with histories and/or documentation of having been vaccinated with tetanus toxoid (TT) under the Expanded Programme on Immunization in Dar es Salaam and Bagamoyo Tanzania. Using an enzyme-linked immunosorbent assay technique serum levels of TT antibody antibody avidity and distribution of TT immunoglobulin (Ig) G subclass antibodies were determined in 207 apparently healthy women. A TT antibody level of 0.1 IU/ml was considered protective. 99% and 100% of women in Dar es Salaam and Bagamoyo respectively had a TT antibody level of 0.1 IU/ml or higher. Anti-toxin binding avidity was found to be high in most of the women. In addition to TT IgG3 subclass antibody TT IgG1 subclass antibody was the most dominant subclass type. A substantial number of women also had TT IgG2 and TT IgG4 subclass antibody responses. A better recording system on TT immunization is recommended to avoid hyperimmunization of women and to optimize the cost-effectiveness of the immunization program. (authors)

A study was undertaken to determine the serological response in children (aged 1-15 years) immunized with diphtheria-pertussis-tetanus vaccine (DPT) alone or with a tetanus toxoid (TT) booster dose under the Expanded Programme on Immunization in Dar es Salaam and Bagamoyo, Tanzania. Using an ELISA technique, serum levels of anti-TT antibody, antibody avidity and anti-TT IgG subclasses were determined in 138 apparently healthy children. Our findings revealed that 94.7% and 98% of children aged 1-5 years in Dar es Salaam and Bagamoyo, respectively, had anti-TT antibody levels above that considered protective (> or = 0.1 IU/ml). Among 6-15-year-old children, 53.3% in Dar es Salaam and 55% in Bagamoyo had anti-TT antibody levels > or = 0.1 IU/ml. The avidity index of anti-TT antibodies was high in most of the younger children, 84.2% in Dar es Salaam and 92% in Bagamoyo. Significantly fewer older children in Dar es Salaam and Bagamoyo (53.3% and 50%, respectively) had high avidity index antibodies. The predominant anti-TT IgG subclasses were IgG1 and IgG3. It is concluded that the current DPT immunization schedule provides adequate tetanus immunity for children under 5. However, about half of the older children had no protection against tetanus.

The purpose of this study was to investigate in vitro the apoptosis- and necrosis-inducing potential of eluates from three heat-polymerized and four autopolymerized poly(methyl methacrylate)-based denture base resins. Our hypothesis was that the rate of cell death by apoptosis and/or necrosis induced by such denture base resins could be an important indicator of their cytotoxicity degree. U-937 human monoblastoid cells were exposed for 24 h and 48 h to eluates of 0.1 g/ml, 0.2 g/ml, 0.4 g/ml, and 0.8 g/ml extracted for 24 h and 48 h. The characteristics of apoptosis and necrosis were evaluated by flow cytometry and light and electron microscopy. Eluates from all resins enhanced cell death by apoptosis and necrosis in U-937 cells in a dose- and time-dependent fashion. Eluates from autopolymerized resins yielded higher percentages of apoptosis and necrosis than the heat-polymerized ones. The results support our hypothesis that eluates of poly(methyl methacrylate)-based denture base acrylic resins activate death-signaling pathways, and that the extent of this process reflects their biocompatibility degree.

Annexin II (AII) belongs to a family of glycoproteins that bind negatively charged phospholipids in the presence of calcium. The annexins exert various biological functions. We have previously shown that soluble AII suppresses mitogen-induced lymphoproliferation in vitro. In this study we address the question of whether soluble AII may also affect immunoglobulin secretion. Mononuclear cells from peripheral blood were stimulated with pokeweed mitogen in vitro and immunoglobulin-secreting cells were quantified using an ELISPOT assay. Retroplacental serum and soluble AII significantly inhibited secretion of IgG and IgM when added at concentrations that did not affect lymphoproliferation or cell viability. The inhibitory effect was dose- and time dependent. Significant suppression was observed when soluble AII was added at concentrations of 0.1 and 0.01 microg/ml. The strongest inhibition was observed when soluble AII or retroplacental serum was added initially. The data demonstrate that soluble AII can suppress immunoglobulin secretion in vitro. AII seems to be a potent immunosuppressive substance. The presence of high levels of soluble AII in retroplacental serum may indicate a possible immunomodulatory role in normal pregnancy.

In a prospective study of psychobiological responses in patients with operable breast cancer, psychological data were collected one day before surgery and immunological data one day before and seven days after surgery.Explore psychoimmunological correlates related to primary surgical treatment of women with operable breast cancer.Distress was assessed with Impact of Event Scale (IES), depression with Montgomery-Aasberg Depression Rating Scale (MADRS), coping with Mental Adjustment to Cancer (MAC) scale, emotional suppression with Courtauld Emotional Control scale (CECS) and neuroticism with EPQ-N. Number of lymphocytes and subsets of lymphocytes were analyzed using a flow-cytometric method.Intrusive anxiety and anxious preoccupation were statistically significant inversely correlated to number of lymphocytes, B, T total and T4 lymphocytes and depression to B and T4 lymphocytes using Bonferroni's correction for multiple testing. Multivariate analyses including menopausal status, type of surgery and health behaviour variables demonstrated an independent, inverse effect of depression on total number of lymphocytes, T total and T4 lymphocytes 7 days after surgery. Pre-post immune changes were influenced reversely by depression (decreased) and intrusion (increased).Psychological parameters have a statistically significant impact on the number of lymphocytes and subsets of lymphocytes.

Investigations were performed on sera from blood donors, pregnant women, patients with polyarthritis and from patients with clinical suspicion of syphilis in Dar es Salaam using Borrelia burgdorferi (Bb) flagellar antigen in a second generation ELISA test from DAKO A/S, Denmark, for specific IgM or IgG antibodies. An IgM and or IgG seropositivity rate of 30/100 (30%), 19/50 (7.2%), 10/20 (50%) and 11/20 (55%) was found in sera from the respective groups. These results compare with a Bb seroprevalence rate of 4/100 (4%), 1/52 (2%) and 363/5024 (7.2%) in blood donors, in pregnant women and in patients investigated serologically for Lyme borreliosis (Lb) respectively in Bergen, Norway, where cases of Lb are detected regularly. The high prevalence of antibodies to Bb flagellar antigen in Dar es Salaam, Tanzania where clinical conditions including erythema migrans, arthritis, mycocarditis and CNS diseases as well as tickbites are found call for further clinical, entomological and laboratory investigations.

The expression of Fc gamma receptors (Fc gamma R) and annexin II in 20 placentae (range 8-27 weeks' gestation) and in 3 full-term placentae was studied using monoclonal antibodies (mAbs) and soluble immune complexes. Functionally active Fc gamma R was detected on the trophoblast, endothelial cells, and stromal cells (Hofbauer cells) from the 8th week of gestation. Fc gamma RI (mAb 32.2) and Fc gamma RIII (mAb 3G8) were detected only on Hofbauer cells, whereas Fc gamma RII (IV3 and C1KM5) were detected both on Hofbauer cells and endothelial cells. Fc gamma RIII (anti-Leu-11b) and the IgG-binding molecule annexin II (mAb B1D6) were expressed by Hofbauer cells, endothelial cells, and the trophoblast. There was some variation in staining among the different specimens, but the number of positive cells as well as the staining intensity increased from the first to the second trimester. In first trimester placenta, staining was localized both to the syncytio- and cytotrophoblast, with the strongest intensity in the cytotrophoblast and at the boundary between the two cell layers. In second and third trimester placenta, staining was localized to the syncytiotrophoblast. The localization and distribution of Fc gamma R on the trophoblast during ontogeny is of interest with regard to its presumed role in the transport of IgG from mother to fetus.

Receptors for the Fc-part of IgG (Fc tau R) in stratum granulosum of normal human skin were examined using cryosections and indirect immunofluorescence staining with 1) soluble immune complexes and 2) monoclonal antibodies (MoAbs) against different types of Fc tau R, i.e. 32.2 (anti-Fc tau I-CD64), IV.3 (anti-Fc tau RII-CD32) and Leu 11b (anti-Fc tau RIII-CD16). The immune complexes gave staining corresponding to stratum granulosum in sections from all skin specimens. Inhibition experiments showed that pre-incubation of the sections with monomeric and heat-aggregated human IgG, periodic acid and formaldehyde inhibited the immune complex binding. F(ab')2 containing immune complexes did not bind to the skin sections. The MoAb 32.2 gave granular and Leu 11b linear staining corresponding to stratum granulosum. In addition, both IC, 32.2 and Leu 11b gave weaker staining of keratinocytes in other parts of the epidermis. IV.3 stained epidermal Langerhans' cells and were unreactive with other epidermal cells. Indirect immunofluorescence staining with MoAbs against IgG subclasses showed the presence of all IgG subclasses in stratum granulosum. The results show that granulosum cells express both high- and low-affinity IgG receptors and in vivo bound IgG. The data point to a role for stratum granulosum in cutaneous immunity.

The expression of CD59, a complement regulator of the formation and function of the terminal cytolytic membrane attack complex, was studied in human normal nervous tissue by immunohistochemical markers using two monoclonal antibodies 1F5 and MEM43. CD59 was present on Schwann cells, neurons and endothelial cells in the peripheral nervous system (PNS), and on Schwann cells in culture. In the central nervous system (CNS) CD59 was found predominantly on endothelial cells. There was also a diffuse staining of white and grey matter of the spinal cord and brain, presumably of microglia, oligodendrocytes, astrocytes and neurons, as these cells were CD59 positive in culture. Furthermore, CD59 was detected in the cerebrospinal fluid (CSF) of healthy individuals. CD59 in the PNS and CNS was glycosyl-phosphatidylinositol linked and had a molecular weight of 19,000-25,000. The presence of CD59 on various cells of the nervous system and in the CSF suggests that regulation of complement activation by this protein is important in neural host defence mechanisms.

Serum levels of immunoglobulin classes and IgG subclasses were determined in healthy seronegative (n = 50) and in HIV-1 seropositive adults (n = 50) from Tanzania, a region with heterosexual HIV-1 transmission pattern. The mean levels of total IgG, IgG1, IgG3, IgA, IgM, and IgD obtained were found to be significantly higher in HIV-1 seropositive sera than in control sera. The mean IgA, IgM, IgD and IgG3 levels showed an increasing trend with progression from asymptomatic phase to AIDS phase. The mean levels for total IgG, IgG1 and IgG2 remained constant while that for IgG4 decreased with progression to AIDS phase. From the findings, it is concluded that polyisotypic hypergammaglobulinaemia and serum IgG subclass changes occur in HIV-1 seropositive individuals in Tanzania. The characteristic changes observed for IgD, IgG3 and IgG4 levels with evolution from asymptomatic to AIDS phases could be of value in monitoring disease progression.

IgG-Fc receptors (FcR) are present on most immune competent cells. We have examined FcR in skin lesions from 8 patients with stationary plaque psoriasis and 12 patients with highly active psoriasis using MoAbs against FcR and binding of soluble immune complexes. FcR in serum were measured in ELISA. The patients were treated with cyclosporin (n = 5), acitretin (n = 7) and Goeckerman regimen (n = 8). As controls served 8 skin biopsies and 22 sera from healthy individuals. Highly active psoriatic lesions showed strongest activity for FcRI, II and III and immune complex binding. The FcR+ mononuclear cells were located perivascularly and along the dermo-epidermal junction. The FcR activity decreased in correlation to the improvement following therapy. Epidermal Langerhans cells (LC) were positive for FcRII and immune complex binding. FcR activity on LC decreased during therapy. Keratinocytes expressed FcRI and III, irrespective of disease activity and therapy. FcR levels were lower in sera from psoriatics than in controls, median 0.15 vs. 0.27 (p0.01), and not correlated to disease activity. In 4 patients the FcR levels increased during therapy. The reduced levels of FcR in psoriatic sera might be due to consumption in the skin or anti-FcR autoantibodies.

Sera from 52 patients with psoriasis and 106 controls were tested for IFN-tau, IFN-alpha 2 and TNF-alpha in ELISA and for total IFN activity using an infectivity inhibition micromethod. Psoriasis patients had lower serum levels of IFN-tau than had the controls: median 0.10 ng/ml vs. 0.16 ng/ml (p = 0.01). The highest median serum IFN-tau levels were in patients with peripherally spreading psoriasis, 0.10 ng/ml, and acute guttate psoriasis, 0.09 ng/ml. Patients with stable plaque psoriasis had lower serum IFN-tau levels (median 0.0) than those with other forms of psoriasis, or blood donors. The serum levels of IFN-alpha 2, total IFN activity and TNF-alpha did not differ between the psoriasis and control group. Treatment with cyclosporin, acitretin and the Goeckerman regimen increased the total IFN activity, but did not affect the levels of IFNs nor TNF-alpha.

Complement receptors for C3b/C4b (CRI) on erythrocytes (ERC1) and renal glomeruli (GCR1) were examined in patients with different types of renal disorders. Normal ECR1 activity was found on erythrocytes from patients with IgA glomerulonephritis, benign nephrosclerosis and other types of renal diseases. In patients with systemic lupus erythematosus (SLE) and glomerulonephritis ECR1 activity was low or absent in 75% of the patients. The GCR1 activity, however, was normal except in areas with complement deposits where GCR1 activity was abolished. During treatment with corticosteroids and azathioprine of patients with SLE the clinical response was followed by increased functional ECR1 activity. In those patients who did not respond the ECR1 activity was persistently low. Three patients with renal transplant all showed increased ECR1 activity.

Cryostat sections of human endometrium bound sheep erythrocytes (E) sensitized with rabbit IgG antibody (A), (EA). Unsensitized E were not bound. Native, heat-aggregated IgG and Fc fragments of IgG inhibited the binding of EA, whereas IgM, IgA and F(ab')2 fragments of IgG did not. The data indicate the presence of receptors for the Fc part of IgG (FcR). Using immune complexes of horseradish peroxidase (HRP) and rabbit IgG antibodies to HRP and monoclonal antibodies (mAbs), FcR were located to the glandular epithelial and endothelial cells, macrophages and predecidual cells of the stroma. These structures were also stained by mAbs against all three FcR classes and a 40-kD low affinity placental FcR. Preliminary results indicate that the expression of FcR varies during different stages of the menstrual cycle. FcR in the endometrium may play a rôle in local immunoregulation necessary for nidation and development of the blastocyst.

The IgG subclass distribution of non-receptor muscle antibodies was examined in 15 myasthenia gravis (MG) sera, employing an indirect haemagglutination-immunofluorescence technique. Four sera contained only IgG1, 4 contained only IgG4 and 7 contained both IgG1 and IgG4 muscle antibodies. IgG2 and IgG3 antibodies were not found. Among 11 patients with a defined thymus pathology 8 had thymoma and 3 had thymic atrophy, but there was no correlation between antibody subclass pattern and thymic pathology. Patients with both IgG1 and IgG4 antibodies tended to have the longest disease duration. We conclude that IgG non-receptor muscle antibodies in MG are of the IgG1 and/or IgG4 subclasses, irrespective of thymic pathology.

Mental and physical health are both at risk under conditions of prolonged remoteness from home and removal from normal social support networks. This article examines relevant data from small groups isolated in (a) Antarctic summer stations, (b) a Transantarctic traverse expedition, and (c) a spacecraft simulator capsule.

Fc-receptors for IgG (FcR) on epidermal cells in suspension were studied using soluble immune complexes and monoclonal antibodies (MoAbs) against FcR I, FcR II and FcR III using an indirect immunofluorescence technique. The binding of immune complexes demonstrated that most Langerhans' cells (greater than 95%) and a proportion of keratinocytes (25 +/- 6%) expressed functional FcR activity. The reactivity with MoAbs showed that epidermal cells possess different types of FcR. Langerhans' cells reacted only with IV.3 (anti-FcR II/-CDw32). A varying percentage of keratinocytes reacted with 32.2 (anti-FcR I/-CD64) (18 +/- 10%), Leu 11b (anti-FcR III/-CD16) (19 +/- 6%) and B1D6 (against a placental FcR) (35 +/- 8%). Both with immune complexes and MoAbs the staining was strongest along the cell surface, but cytoplasmic staining was also regularly present. The data add further support to the contention that keratinocytes have an immune function. FcR on epidermal cells may play an immunoregulatory role interacting with isotypes and cytokines in the skin. Keratinocyte-produced soluble FcR could also be an immunological mediator.

Fc receptors for IgG, FcRI (CD64), FcRII (CD32), and FcRIII (CD16) in human placenta were studied by indirect immunohistochemistry using avidin-biotin peroxidase complexes for the staining of cryostat sections. The MoAb 32.2 against FcRI stained cells in the loose connective tissue of the placental villi. The MoAb IV3 (FcRII) and C1KM5 (FcRII) also stained stromal cells and in addition stained the endothelium of the placental villi. The MoAb anti-Leu-11b against FcRIII and B1D6 against a 40-kDa FcR from placenta stained both stromal cells and endothelium as well as the fetal trophoblasts lining the villi. The MoAb 3G8 (FcRIII) also stained trophoblasts and stromal cells but did not stain the endothelium. The heterogeneity of FcR expression on human placenta is established. The function of the different receptors is still unclear.

Eleven patients presented with a second primary cancer during follow-up after surgery for gastric carcinoma. In these patients the serum concentrations of C1-INH and IgG prior to gastric cancer surgery were similar to those of 53 patients with recurrence of gastric cancer. In these two groups, the preoperative C1-INH concentrations were higher and IgG lower (P less than 0.001 and P less than 0.05) when compared to 36 patients alive and disease-free 5 years after surgery. The median time between surgery and signs of recurrence was 11 months, whereas the median time until signs of the second primary cancer was 4 years. A patient with gastric carcinoma who pre-operatively has high C1-INH and low IgG is liable either to have recurrence or to develop a second primary cancer. Our data indicate that these variables represent a cancer susceptibility feature appropriate to the host.

The distribution of Fc-receptors for IgG (FcR) on human epidermal cells (EC) was characterized in situ using monoclonal antibodies (MoAbs) by indirect immunofluorescence staining of cryosections. The results showed heterogeneity of FcR expression on Langerhans' cells (LC) and keratinocytes (KC). The MoAb IV.3 against FcR II (CDw32) gave granular staining of most LC whereas the MoAb 32.2 against FcR I (CD64) occasionally stained a few dendritic cells. 32.2 demonstrated weak granular staining along the outer aspect of KC in stratum spinosum and stratum basale and intense staining of stratum corneum and stratum granulosum. The MoAbs Leu 11b against FcR III (CD16) and B1D6 reacting with a placental FcR with low affinity for IgG gave intense linear membrane staining of KC. Leu 11b produced strongest staining of stratum granulosum and B1D6 the strongest staining of stratum spinosum and basale. The results confirm our previous observations of FcR in situ on LC and KC in normal skin using functional assays and demonstrate that these EC possess different types of low affinity FcR. The data support the contention of an immune function of KC. FcR may be mediators for interaction between KC and LC. The FcR activity in stratum granulosum may have an immune function as a barrier against microorganisms and other antigens.

The ontogenesis of Fc gamma receptors (FcR) and C3b/C4b receptors (CR1) was studied in peripheral nerves from ten fetuses aged from 20 to 38 weeks using immunohistochemical and functional assays. Monoclonal antibodies (mAbs) against FcR and CR1 stained nerve fibers at 10 weeks of gestation and the staining intensity increased during nerve maturation. FcR and CR1 are probably expressed on Schwann cells and are early markers during the development of peripheral nerves. Functional FcR activity was detected in nerve sections before initiation of myelination, which occurs at approximately 18-19 weeks, whereas functional CR1 activity was found in the sections after myelination. Functional CR1 activity may, therefore, be related to myelin. The ontogenesis of FcR and CR1 was also studied on Schwann cells in culture from three fetuses aged 14, 16 and 19 weeks, using immunofluorescence technique with mAbs. The FcR and CR1 are lost on cultured Schwann cells. This suggests that the receptors are not intrinsic to the cells or that Schwann cells require axonal contact for the expression of FcR and CR1.

Glomeruli in cryostat sections of human kidney adsorbed sheep erythrocytes (E) sensitized with unheated rabbit antiserum (A). EDTA and immune complexes composed of F(ab′) 2 antibody and complement inhibited the binding of EA. E sensitized with heated A and soluble immune complexes composed of purified IgG antibodies did not bind, indicating a lack of Fcγ receptors. Sections washed in saline or sections prepared of perfused kidney did not bind any of the EA. Apparently the glomerular C3b receptor mediates the binding of EA which activate complement present in the tissue.

The mixed haemagglutination technique was used to demonstrate IgG antibodies to peripheral nerve tissue in sera from patients with the Guillain-Barré syndrome. The clinical effect and the effect on the antibodies of plasma exchange were examined in 18 patients. Neurological examination with muscle testing and neurophysiological examination of the patients were performed before and immediately after plasma exchange. Before the exchange antibodies were detected in sera from 11 of the patients. These patients showed clinical improvement during the treatment. After plasma exchange, antibodies were detected in sera from only two of the patients. The seven patients without detectable antibodies showed no clinical improvement.

Serum concentrations of C4, IgG, IgA, and IgM were followed in 8 selected patients with myasthenia gravis (MG) during a 5-day course of plasma exchange (PE), using donor plasma as a replacement solution. C3 activation products (C3b, iC3b and C3c) and the terminal SC5b-9 complement complex were measured in 4 of the patients. All patients improved during the treatment, including 2 patients without detectable antibodies to AChR in serum. The main findings of the study were marked complement activation and an approximately 50% fall in the serum concentrations of IgM and C4 during PE, independent of the concentrations in the donor plasma. The concentrations of IgG and IgA did not change significantly. The fall in C4 during PE is presumably caused by C4 consumption. We postulate that the fall in IgM is an effect of a complement-induced vasodilatation and that PE-induced complement consumption may influence the effect of PE in patients with MG.

Immune complexes of horseradish peroxidase (HRP) and rabbit IgG antibodies to HRP were used to study the Fcgamma receptors in normal human placenta. Cryostat sections of placental tissue were incubated with the complexes, and the peroxidase activity was revealed histochemically. The bound complexes were localized to the apical surface of the trophoblasts and endothelial cells of the fetal stem vessels. Binding also occurred within the wall of some fetal vessels, to stromal cells and occasionally to areas corresponding to the trophoblastic membrane. The strongest binding was obtained with immune complexes prepared at slight antigen excess. Eight- to sixteen-fold increased concentration of human and rabbit IgG was needed to block the binding of immune complexes. Bovine and porcine IgG did not block the binding. Treatment of tissue sections with neuraminidase enhanced the binding activity of the receptors. The technique is very convenient for studies of Fcgamma receptors in tissue. However, unfixed frozen placental tissue was not suitable for ultrastructural studies.

The inflammatory mononuclear cell infiltrates observed in lesional skin from patients with discoid lupus erythematosus (DLE), sarcoidosis, and secondary syphilis have been characterized in situ. Immunological markers (human T lymphocyte antigens and receptors for sheep erythrocytes, C3b, C3d and Fc gamma) were studied by using immunofluorescence tests with IgG F (ab´)2 preparation of anti-T lymphocyte serum, hemadsorption with tissue sections, and tests with soluble immune complexes of peroxidase. In DLE, T lymphocytes were the dominant cell type. In sarcoidosis, the epithelioid cells, including giant cells, had markers similar to macrophages. The lymphohistiocytic cells consisted mainly of macrophages, some T lymphocytes and a few B lymphocytes. In secondary syphilis (condylomata lata), macrophages and T lymphocytes were the dominant cell types, and relatively few B lymphocytes were detected.

Cryostat sections of placental tissue strongly adsorbed erythrocytes sensitized with IgG antibodies of human, rabbit, and guinea pig origin. No adsorption occurred using erythrocytes sensitized with F(ab')2 fragments. The reaction was strongly inhibited by intact IgG and by Fc fragments, weakly inhibited by pFc' fragments, and not inhibited by Facb and F(ab')2 or albumin. These properties are similar to those of corresponding receptors in normal lymphoid tissues. Results obtained with sections of hydatidiform mole showed that the reaction occurred with the trophoblastic tissue. Porcine placenta had no Fc receptor activity. The presence of an Fc receptor in human placental tissue may therefore be of significance for the selective transfer of IgG from mother to foetus.

Glomeruli in Cryostat sections of foetal and adult renal tissues adsorbed sheep erythrocytes sensitized with IgM antibody and human or mouse complement (EAC). Activated complement was essential for the reaction to occur. The receptor had specificity for the C3b fragment of C3 and is probably of protein or glycoprotein nature. Complement receptors in glomeruli may explain the deposition of complement components or complement-containing complexes in immune-complex glomerulonephritis.

Crysotat sections of human choroid plexus adsorbed erythrocytes sensitized with IgG antibodies of human and rabbit origin. No adsorption occurred when the erythrocytes were sensitized with F(ab')2 or Facb fragments. The reaction was strongly inhibited by intact IgG and by Fc fragments and not inhibited by Facb and F(ab')2 or albumin. These properties are similar to those of corresponding receptors in human placenta. The presence of an Fcgamma receptor in choroid plexus may be of significance for the transfer of IgG from blood to cerebrospinal fluid.

Receptors for C3b (C3R) in human spleen and kidney were studied using haemadsorption to cryostat sections. The indicator cells, ovine erythrocytes (E) coated with rabbit IgM antibody (A) and human C3b (EAC) adhered strongly to the glomeruli in renal tissue and to the white pulp of spleen. Titration experiments showed that avidity of the two populations of C3R was equal. Activity was independent of Ca++ and Mg++. Periodic acid, formaldehyde, high salt concentrations and trypsin abolished, whereas neuraminidase enhanced the activity. Various temperatures and pHs affected the two populations of C3R similarly. The results obtained indicate that the C3R in spleen and kidney are similar.

Sera from patients with gonorrhoea were used to study the specificity of human antibodies against determinant a of endotoxin from gonococcal strains 8551, V, and VII. The sera were tested by an indirect haemagglutination technique before and after absorption with endotoxin from the same strains. The sera were used untreated and treated with mercaptoethanol (ME). The untreated and ME-treated sera showed antibody activity against all the a determinants when examined unabsorbed. After absorption with any of the endotoxin preparations the sera usually demonstrated antibody activity against one or both of the other preparations. The pattern of reactivity thus observed differed from one serum to another. Treatment of sera with ME resulted in an altered pattern of reactivity of four of the five sera. The results indicate multispecificity of human antibodies against the a determinants.