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Isolated orbital roof fractures are rare fractures that usually occur in conjunction with other facial bone fractures during high velocity trauma. This report concerns a patient with an isolated orbital roof fracture with encephalocele, including its diagnosis, surgical management, and clinical follow-up. This case required a multidisciplinary approach to safely repair the fracture, reduce the encephalocele, restore the orbital volume, and restore the patient’s form and function.

MAS related G-protein coupled receptor X2 (MRGPRX2) is a G-protein coupled receptor (GPCR) expressed in human mast cells that has been implicated to play an important role in causing pseudo-allergic reactions as well as exacerbating inflammation during asthma and other allergic diseases. Lactic acid, a byproduct of glucose metabolism, is abundantly present in inflamed tissues and has been shown to regulate functions of several immune cells. Because the endogenous ligands for MRGPRX2 (substance P and LL-37) are elevated during pathologic conditions such as cancer and asthma, and given that lactic acid levels are also enhanced in these patients, we explored the role of lactic acid in regulating mast cells response via MRGPRX2 and MrgprB2, the mouse orthologue of the human receptor. We found that lactic acid suppressed both the early (Ca(2+) mobilization and degranulation) and late (chemokine/cytokine release) phases of mast cell activation; this data was confirmed in LAD2, human skin and mouse peritoneal mast cells. In LAD2 cells, the reduction in degranulation and chemokine/cytokine production mediated by lactic acid was dependent on pH. In agreement with our in vitro studies, lactic acid also reduced passive systemic anaphylaxis to compound 48/80 (a known MRGPRX2/MrgprB2 ligand) and skin inflammation in a mouse model of rosacea that is dependent on MRGPRB2 expression on skin mast cells. Our data thus suggest that lactic acid may serve to inhibit mast cell-mediated inflammation during asthma and reduce immune response during cancer by affecting mast cell activation through MRGPRX2.

Mast cells are tissue-resident innate immune cells known for their prominent role in mediating allergic reactions. MAS-related G-protein coupled receptor-X2 (MRGPRX2) is a promiscuous G-protein coupled receptor (GPCR) expressed on mast cells that is activated by several ligands that share cationic and amphipathic properties. Interestingly, MRGPRX2 ligands include certain FDA-approved drugs, antimicrobial peptides, and neuropeptides. Consequently, this receptor has been implicated in causing mast cell-dependent pseudo-allergic reactions to these drugs and chronic inflammation associated with asthma, urticaria and rosacea in humans. In the current study we examined the role of osthole, a natural plant coumarin, in regulating mast cell responses when activated by the MRGPRX2 ligands, including compound 48/80, the neuropeptide substance P, and the cathelicidin LL-37. We demonstrate that osthole attenuates both the early (Ca2+ mobilization and degranulation) and delayed events (chemokine/cytokine production) of mast cell activation via MRGPRX2 in vitro. Osthole also inhibits MrgprB2- (mouse ortholog of human MRGPRX2) dependent inflammation in in vivo mouse models of pseudo-allergy. Molecular docking analysis suggests that osthole does not compete with the MRGPRX2 ligands for interaction with the receptor, but rather regulates MRGPRX2 activation via allosteric modifications. Furthermore, flow cytometry and confocal microscopy experiments reveal that osthole reduces both surface and intracellular expression levels of MRGPRX2 in mast cells. Collectively, our data demonstrate that osthole inhibits MRGPRX2/MrgprB2-induced mast cell responses and provides a rationale for the use of this natural compound as a safer alternative treatment for pseudo-allergic reactions in humans.

The concept of sustainability is a theme that is both old and new. It is old from the perspective of Native Americans whose “seven generations” thinking considers simultaneously ancestors and futur...

INTRODUCTIONIn November 2015 the Journal of Geoscience Education Editorial Board met to review and discussed the criteria for curriculum and instruction (CI teaching approaches; professional development; or outreach to schools or the general public. We welcome innovations targeted at any grade level that are used in either formal or informal settings. All C&I papers must be grounded in appropriate educational literature, and must provide evidence of how the proposed innovation meets its learning goals. The following criteria should be met:1. Title: The title sets the stage for the paper. It informs the reader about the topic of the paper. Specific to C&I papers, the title should describe the type of educational innovation and the setting where it was implemented.2. Abstract: The paper must include an informational abstract of no more than 250 words that summarizes the purpose of the educational innovation, what takes place during the innovation, the data that supports the effectiveness of the innovation, and ''lessons learned'' that could help readers implement the innovation elsewhere. It is a succinct summary of the paper itself, rather than an introduction to the paper.3. Purpose and Learning Goals: The purpose of the educational innovation is clearly explained. Where appropriate, this includes learning goals stated in terms of what participants should know or be able to do after completing the activity, program, course, or other intervention. …

Topographic maps and aerial photographs are particularly useful when geoscientists are faced with fieldwork tasks such as selecting paths for observation, establishing sampling schemes, or defining field regions. These types of images are crucial in bedrock geologic mapping, a cognitively complex field-based problem-solving task. Geologic mapping requires the geologist to correctly identify rock types and three-dimensional bedrock structures from often partial or poor-quality outcrop data while navigating through unfamiliar terrain. This paper compares the walked routes of novice to expert geologists working in the field (n = 66) with the results of a route planning and navigation survey of a similar population of geologists (n = 77). Results show clearly that those geologists with previous mapping experience make quick and decisive determinations about field areas from available imagery and maps, regardless of whether they are or not physically present in the field area. Recognition of geologic f...

In this commentary, we argue that social capital theory, the idea that membership in a group creates opportunities to acquire valuable information and resources from other group members, is a usefu...

The gastrointestinal (GI) tract and associated organs are some of the most metabolically active tissues in an animal. Hence, when facing food shortages or poor food quality, an animal may reduce the size and function of their GI tract to conserve energy. We investigated the effects of prolonged starvation and varying food quality on the structure and function of the GI tract in a detritivorous catfish, Pterygoplichthys disjunctivus, native to the Amazonian basin, which experiences seasonal variation in food availability. After 150 days of starvation or consumption of a wood-diet too low in quality to meet their energetic needs, the fish reduced the surface area of their intestines by 70 and 78%, respectively, and reduced the microvilli surface area by 52 and 27%, respectively, in comparison to wild-caught fish consuming their natural diet and those raised in the laboratory on a high-quality algal diet. Intake and dietary quality did not affect the patterns of digestive enzyme activity along the guts of the fish, and the fish on the low-quality diet had similar mass-specific digestive enzyme activities to wild-caught fish, but lower summed activity when considering the mass of the gut. Overall, P. disjunctivus can endure prolonged starvation and low food quality by down-regulating the size of its GI tract.

Compliance with environmental regulations is becoming more and more costly for manufacturers as government scrutiny and global trade agreements become more stringent. Metal-cutting fluid use and disposal is a major concern as these environmental issues become more prominent. Gaining a clear understanding of the costs associated with machining coolant/lubricant use can be difficult. Many factors impact this cost, such as the original purchase price, maintenance costs, disposal management and fees, and performance factors related to the particular fluid. This paper develops a detailed cost and performance-based methodology for machining coolant/lubricant selection. A model by which to evaluate the relative impacts of coolant/lubricant decisions on the unit workpiece cost of production is described. At present, a widely accepted methodology is not available for this purpose. The model presented here will assist manufacturing companies of all types in making this critical decision.

PurposeTo develop a decision framework for the planning and development of a flexible manufacturing system (FMS).Design/methodology/approachA systematic weighted property index approach for FMS development decisions is developed to evaluate various design options. This methodology converts design property values of differing orders of magnitude into a unitless system where an overall evaluation of the options can be made.FindingsMajor design choices related to the implementation of an educational FMS are identified, and considerations affecting each choice are discussed. A methodology for the selection of the appropriate FMS is then developed and demonstrated.Practical implicationsProvides a useful framework for evaluating various options in FMS development and selecting an appropriate system for a given environment and situation.Originality/valueIdentifies the major design choices related to the implementation of an educational FMS, provides practical examples taken from the development of FMSs at Southwest Missouri State University and the University of Missouri‐Rolla, and presents a systematic methodology for FMS design decision making.

Over the past quarter century, much effort has been devoted to the design and development of simulation modeling languages, and to methods for the development of simulation models themselves. Less effort, however, has been expended on the design of the experimental models upon which simulation studies are based. This paper describes a methodology for the determination of near optimal solutions considering experimental design and simulation modeling. Using this methodology, simulation scenarios are created and analyzed using an analysis of variance (ANOVA)-based experimental design. This paper also presents an application of this method in analyzing a manufacturing system design problem.

The Late Devonian Mount Waldo pluton is a porphyritic granite that has a magmatic foliation and lineation. Foliation is defined by: (1) preferred orientation of potassium feldspar phenocrysts and biotite crystals, and (2) the anisotropy of magnetic susceptibility (AMS). AMS alone defines the lineation. The carrier of the AMS signal is multidomain magnetite, confirmed by petrographic observation, high bulk susceptibility (generally >3 E3 SI units) of samples, and results of isothermal remanent magnetization experiments. AMS data from 26 sites in the pluton consistently show a subhorizontal north–south-trending lineation (defined by the orientation of the maximum axis of the AMS ellipsoid) and a subvertical north–south-striking foliation (whose pole is the minimum axis of the AMS ellipsoid). At individual sites, the feldspar and AMS foliations are parallel. The lack of evidence for significant solid state deformation in the pluton suggests that both the lineation and foliation are entirely magmatic in origin. The pluton's relatively small size (15 km diameter) and shallow emplacement depth (≤3 kbar) suggest that it was in its magmatic state for a short time, probably less than one million years. The orientation of the lineation and foliation is consistent with their formation due to a small increment of crustal-scale strain absorbed by the pluton in its geologically brief magmatic state. If so, these fabrics record a Late Devonian crustal-scale strike-slip stress regime that may also have driven dextral movement on the neighboring Norumbega Fault Zone.

Sources of individual differences in scientific problem solving were investigated. Participants representing a wide range of experience in geology completed tests of visuospatial ability and geological knowledge, and performed a geological bedrock mapping task, in which they attempted to infer the geological structure of an area in the Tobacco Root Mountains of Montana. A Visuospatial Ability × Geological Knowledge interaction was found, such that visuospatial ability positively predicted mapping performance at low, but not high, levels of geological knowledge. This finding suggests that high levels of domain knowledge may sometimes enable circumvention of performance limitations associated with cognitive abilities.

Organic anion transport in polarized epithelia and macrophages has previously been studied by monitoring the efflux of fluorescent organic anion dyes from cells. We adapted this strategy to the study organic anion transport in lymphocytes. Cloned lymphoma cells and normal and activated human T cells were loaded with a membrane-impermeant, organic anion dye (Lucifer Yellow) by electroporation. Dye efflux in lymphocytes was rapid, energy-dependent, and inhibitable by organic anion transporter inhibitors. Dye efflux could not be attributed to the effects of electroporation. In addition, electroporated, dye-loaded T helper cells retained the ability to properly respond to specific antigen. Thus, dye loss occurred in viable, functionally competent cells. These experiments demonstarate that electroporation is an effective means of loading cells with Lucifer Yellow, and that lymphocytes possess organic anion transporters that are functionally similar to those previously described for secretory epithelia and macrophages.

Antilymphocyte antibodies, including autoantibodies to CD4, have been reported in AIDS patients and are postulated to contribute to T cell depletion and immunologic dysfunction. In this paper, we characterize and localize binding sites of human anti-CD4 autoantibodies from a number of HIV+ patients. Epitope mapping by ELISA and Western blotting, together with cross-competition experiments, showed that common autoepitopes were localized to at least two topographically separate sites on the fourth domain of sCD4. These sites were partially dependent on the carboxyl terminus of the soluble molecule and were not exposed on full length membrane CD4, even under denaturing Western blotting conditions. Peptide screening identified peptides from the fourth and third domains that were recognized by several, but not all, anti-CD4 serum samples. Soluble CD4 affinity-purified antibodies were predominantly IgG1 and were not induced to bind mCD4 after gp120 binding to T cells. Analysis of HIV seroconversion panels showed that the appearance of anti-CD4 antibodies followed HIV seroconversion by 6 to 12 months and paralleled anti-gp120 reactivity. This suggested a correlation between immune reactivity to envelope and anti-CD4 antibody production. Together, the data indicate that human anti-CD4 antibodies recognize cryptic conformational and linear epitopes on a cleaved form of CD4. These findings suggest that HIV may induce abnormal cleavage of full length CD4, thereby exposing immunogenic self epitopes normally hidden from humoral and cellular immune interactions. This model of abnormal processing of self Ag has general implications for autoantigen exposure in other autoimmune disorders.

We used a panel of in vitro assays to investigate the nature of immune dysfunction in cats infected with FeLV-FAIDS, a naturally occurring, molecularly cloned feline leukemia virus (FeLV) isolate which induces a fatal immunodeficiency syndrome in infected cats. During the asymptomatic period preceding immunodeficiency disease, we were unable to detect any deficits in concanavalin A-induced blastogenesis, xenogeneic mixed-lymphocyte reaction assays, stimulation of lymphocytes by soluble protein antigen, and cytotoxic T lymphocyte assays. However, during this period humoral immune responses in the FeLV-FAIDS-infected cats were dramatically impaired. As early as 9 weeks after virus inoculation, the ability to mount either an IgM or IgG response to soluble protein antigens was lost. Neither B cell function, as assessed by lipopolysaccharide-induced blastogenesis or circulating B cell numbers, as assessed by immunofluorescence, differed between infected and control cats. These results suggests that FeLV-FAIDS infection may impair a subpopulation of T helper cells, that provides help for the production of antibody. Consistent with earlier observations of cats naturally infected with FeLV, our results indicate that early impairment of humoral imunity is an important component of the immunodeficiency syndrome induced by FeLV in cats.

The mechanism of the antiviral activity of sulfated polysaccharides on human immunodeficiency virus type 1 (HIV-1) was investigated by determining the effect of dextran sulfate on the binding of CD4 and several anti-gp120 monoclonal antibodies to both recombinant and cell surface gp120. Dextran sulfate did not interfere with the binding of sCD4 to rgp120 on enzyme-linked immunosorbent assay (ELISA) plates or in solution and did not block sCD4 binding to HIV-1-infected cells expressing gp120 on the cell surface. Dextran sulfate had minimal effects on rgp120 binding to CD4+ cells at concentrations which effectively prevent HIV replication. In contrast, it potently inhibited the binding of both rgp120 and cell surface gp120 to several monoclonal antibodies directed against the principal neutralizing domain of gp120 (V3). In an ELISA format, dextran sulfate enhanced the binding of monoclonal antibodies against amino-terminal regions of gp120 and had no effect on antibodies directed to other regions of gp120, including the carboxy terminus. The inhibitory effects of polyanionic polysaccharides on viral binding, viral replication, and formation of syncytia therefore appear mediated by interactions with positively charged amino acids concentrated in the V3 region. This high local positive charge density, unique to the V3 loop, leads us to propose that this property is critical to the function of the V3 region in mediating envelope binding and subsequent fusion between viral and cell membranes. The specific interaction of dextran sulfate with this domain suggests that structurally related molecules on the cell surface, such as heparan sulfate, may be additional targets for HIV binding and infection.

Tumor cells typically fail to stimulate protective immune response in the autochthonous host. This does not appear to be the result of either inadequate antigenicity or failure to express a normal complement of major histocompatibility complex (MHC) class 1 molecules. To investigate if tumor cells fail to stimulate protective immunity because they fail to activate adequate numbers of T helper cells, we transfected murine fibrosarcoma and melanoma cells with genes encoding syngeneic and allogeneic MHC class II molecules. Fibrosarcoma cells expressing either type of MHC class II molecules failed to induce tumors in syngeneic mice and stimulated T helper cell-dependent antitumor immune responses that protected mice from subsequent challenge with untransfected tumor cells. The antitumor response involved both CD4+ and CD8+ T cells, and appeared to be dependent on at least low levels of innate tumor cell immunogenicity.

The initiation of effective immune responses usually requires presentation of Ags by MHC class I and class II molecules. Although most tumors express MHC class I molecules, MHC class II molecule expression is generally limited to specialized APCs. One reason spontaneous tumors may fail to elicit effective immune responses is that tumor Ags are inefficiently presented by APCs, and adequate T cell-mediated help is not generated. To test this hypothesis, we investigated the possibility of enhancing Th cell stimulation by inducing expression of MHC class II molecules on tumor cells. We transfected a murine fibrosarcoma, Sa1N, with the genes encoding allogeneic (I-Ad) or syngeneic (I-Ak) MHC class II molecules. We then compared the tumorigenic and immunogeneic potential of these transfectants to parental Sa1N tumor cells. Subcutaneous injection of allogeneic or syngeneic transfectants resulted in dramatically fewer tumors than injection of unmodified fibrosarcoma cells, and mice inoculated with MHC class II gene-transfected cells were resistant to subsequent challenge with parental Sa1N cells. Rejection of allogeneic MHC class II Ag+ tumor cells could be mediated by either CD4+ or CD8+ T cells, whereas rejection of secondary challenge with wild-type Sa1N tumor cells required both T cell subsets. These results demonstrate that allogeneic, as well as syngeneic, MHC class II Ag+ tumor cells can stimulate protective antitumor immunity.

A/JCr mice reject Sa1N fibrosarcoma cells genetically engineered to express major histocompatibility complex (MHC) class II molecules and are highly resistant to subsequent challenge with unmodified Sa1N cells. In this report we examine the mechanism by which this protective antitumor immunity is induced. We found that MHC class II antigen-positive tumor cells were no more effective than irradiated, MHC class II antigen-negative cells at inducing secondary protective immunity. Additionally, therapeutic immunization with MHC class II antigen-positive tumor cells had no effect on the growth of admixed Sa1N cells or preexisting Sa1N tumors. Based on these observations, we conclude that the MHC class II antigen-induced immune response is not related to Sa1N-specific antitumor immunity.

Several recent studies have indicated that alterations in expression of major histocompatibility complex (MHC) antigens by tumor cells affects the ability of the host to mount an effective antitumor immune response. To investigate whether newly induced tumors frequently exhibit altered MHC antigen expression, we used methylcholanthrene to induce a series of tumors and elevated MHC antigen expres- sion by these cells. The tumors exhibited a variety of MHC phenotypes in vitro. The nature of their phenotypes suggested that these cells were, in fact, capable of independent and abnormal regulation of MHC class 1 genes. However, when maintained in vivo, these same tumor cells expressed measurable levels of all of the appropriate MHC class I antigens. Thus, newly induced tumor cells are capable of abnormal MHC class I antigen expression. However, there was no obvious correlation between the phenotypes exhibited by these tumor cells in vitro and either their phenotype or their tumorigenic potential in vivo.

Thymus-derived lymphocytes (T cells) have two outstanding characteristics that distinguish them from other lymphocytes: (a) they express two specificities, one for self-antigens, the major transplantation antigens (H) coded by the major histocompatibility gene complex (MHC), and a second specificity for foreign antigenic determinants. (b) T cells must undergo differentiation or maturation in the thymus (1, 2). Apparently, an important step in T-cell differentiation in the thymus is the selection of T-cells' restriction specificity for self-H. This interpretation stems from experiments with chimeras formed by lethally irradiating parental type mice and reconstituting them with F(1) stem cells: the maturing F(1) T cells expressed predominantly the restriction specificities for the recipient parental MHC type (3-8). Alternatively, adult F(1) mice that were thymectomized, lethally irradiated, reconstituted with bone marrow, and then engrafted with a parental thymus had T cells that were restricted predominantly to the thymus donors' H-2 (4-8). The present study first extends these observations to nude mice that are born without a thymus and therefore do not develop functional T cells and second, attempts to study the possibility that suppression may be responsible for the apparent influence of the radioresistant portion of the thymus on T- cell restriction specificities. We tested the immunocompetence and restriction specificities expressed by lymphocytes from F(1) nude mice reconstituted with both parental thymus grafts; our expectation was that suppression of the expression of T-cell restriction specificity should result either in complete immunoincompetence or emergence of only one of the two possible sets of restriction specificities. Nude F(1)mice that simultaneously received thymus gratis from both parents developed spleen cells restricted to both parental H-2 types. These results are compatible with the idea that the thymus' influence on T- cell restriction is via positive selection rather than by suppression.

Sera obtained from normal B10.BR mice were shown to inhibit selectively a specific anti-Ia alloantiserum. Partial purification of the Ia antigenic activity was accomplished by isolation of the high density lipoproteins from these sera by fractional precipitation with sodium phosphotungstate and MgCl2. Both H-2.23 and Iak antigens present in this high density lipoprotein fraction were completely adsorbed by rabbit anti-rat β2-microglobulin immunoadsorbents, whereas specific anti-H-2.23 immunoadsorbents removed only the H-2 activity. These data demonstrate that Ia antigens, like H-2 antigens in the sera of B10.BR mice are associated with high density lipoproteins and further suggest that both H-2 and Ia antigens are associated with a β2-microglobulin-like molecule.

Recent studies from several laboratories have documented the presence of fragments of parathyroid hormone in blood or peripheral tissues or in both. Inasmuch as amino-terminal fragments are known to be biologically active, it has been suggested that fragments, rather than the intact polypeptide of 84 amino acids, might be the active molecular species in tissue fluids. Accordingly, the metabolism of native bovine parathyroid hormone, bPTH-(1-84), was studied in purified renal cortical membranes from several species and correlated with hormonal stimulation of adenylyl cyclase in these membranes in vitro. Analysis of whole incubation mixtures or membrane-bound hormone by gel electrophoresis and gel chromatography after incubation of [3H]bPTH-(1-84) or 125-I-labeled bPTH-(1-84) or unlabeled biologically active bPTH-(1-84) with purified canine renal cortical membranes revealed no evidence of proteolysis, and yet the uncleaved hormone readily stimulated adenylyl cyclase. Kinetic studies of hormone-stimulated adenylyl cyclase activity revealed no difference in rate of onset of activity between bPTH-(1-84) And the active synthetic amino-terminal tetratriacontapeptide bPTH-(1-34), and hence there was no evidence of precursor-product relationship between the native hormone and an active amino-terminal fragment. The results suggest, insofar as the activity detected in these membranes reflects the biological response of the hormone in vivo, that the native hormone is indeed biologically active at the receptor level directly without the requirement for cleavage into active fragments.

We have studied the effects of guanylylimidodiphosphate (Gpp(NH)p), an analogue of GTP, on the stimulation of renal cortical adenylyl cyclase by bovine parathyroid hormone (bPTH, or bPTH-(1-84)). Incubation of canine renal membranes with bPTH-(3-34), a specific antagonist of parathyroid hormone, in either the presence or absence of Gpp(NH)p, prevented subsequently added bPTH-(1-84) from stimulating adenylyl cyclase. The addition of the antagonist to a cyclase system previously activated by both bPTH-(1-84) and Gpp(NH)p, however, produced no inhibition of enzyme activity. Removal of bPTH by washing the membranes virtually abolished activity, but washing after addition of bPTH plus Gpp(NH)p did not prevent continued accumulation of cAMP. The persistence of the activity of the enzyme brought about by the addition of Gpp(NH)p plus bPTH, despite washing or addition of specific inhibitor of bPTH action, indicates that the activity of the hormone-specific adenylyl cyclase in membrane suspensions is independent of cintinuous occupancy of the peptide-hormone receptor by bPTH in the presence of the guanyl-nucleotide analogue.

Congenitally thymusless nude mice that lacked functional T cells were reconstituted with H-2-compatible or -incompatible thymus grafts taken from either fetal, newborn, or adult mice and transplanted under the kidney capsule or subcutaneously. Transplantation with unirradiated fetal (15--17 d) or newborn thymus grafts reconstituted the nude mice as assessed by their subsequent generation of virus-specific cytotoxic T cells in vivo or alloreactive T cells in vitro. The restriction specificity of T cells from homozygous mice was exclusively for the nude host H-2, as shown by direct cytolysis or by cold target competitive inhibition assays. irrespective of whether nude mice were reconstituted with H-2-compatible, semiallogeneic, or H-2-incompatible, unirradiated newborn or fetal thymus grafts (in order of decreasing efficiency of reconstitution). The restriction specificity for the nonhost H-2 of the thymus could not be demonstrated even after primary or secondary sensitization in an infected appropriate F1 environment. These nude mice reconstituted with fetal or newborn grafts were tolerant to the H-2 of the thymus donors. Nude mice transplanted with irradiated adult thymus grafts were reconstituted functionally with syngeneic or semisyngeneic but not with allogeneic thymus grafts. In homozygous nu/nu irradiated heterozygous recipients of F1 thymus grafts, the restriction specificity for the nonhost thymic H-2 could not be elicited upon adoptive sensitization in irradiated and infected F1 heterozygote stimulator mice; in fact, these chimeras' lymphocytes were not tolerant to the nonhost H-2. The discrepancy between the restorative capacity of unirradiated vs. irradiated thymus grafts suggests that precursors of T cells in nude mice can acquire restriction specificity and immunocompetence independently of a conventional, functioning H-2-compatible thymus if exposed to an allogeneic fetal or a newborn thymus that contains functioning thymocytes of donor type but not if reconstituted with an irradiated adult allogeneic thymus.

Murine 6C3HED lymphoma cells were found to rosette with sheep red blood cells (SRBC). Normal C3H lymphocytes did not exhibit this property. This rosetting capacity of 6C3HED cells was found to be an accurate and reproducible means for discriminating between normal and tumor cells. The SRBC receptor on these lymphoma cells appeared to be serologically distinct from that expressed by normal human T lymphocytes since reciprocal blocking experiments demonstrated that inhibitory antisera were not cross-reactive. The expression of the SRBC receptor by the 6C3HED cells appeared to correlate with the expression of a tumor-associated antigen and was spatially related to an antigen expressed by 6C3HED and normal neonatal but not adult mouse cells.

Ovine lentiviruses share genome sequence, structural features, and replicative mechanisms with HIV, the etiologic agent of AIDS. A lamb model of lentivirus-induced lymphoid interstitial pneumonia, comparable to lymphoid interstitial pneumonia associated with pediatric AIDS, was used to investigate production of leukocyte-soluble mediators. Lentivirus-infected lambs and adult sheep with severe lymphoid interstitial pneumonia had significantly elevated levels of spontaneous interferon (IFN) production from pulmonary leukocytes compared with ovine lentiviruses-infected animals with mild or no lesions of lymphoid interstitial pneumonia or non-infected controls. However, peripheral blood mononuclear cells from lentivirus-infected lambs did not spontaneously release significant amounts of IFN. IFN production by pulmonary lymph node lymphocytes was enhanced in the presence of lentivirus-infected alveolar macrophages. Animals with lentivirus-induced disease and spontaneous IFN production had enhanced virus replication within tissues. The ovine lentiviruses-induced IFN had a m.w. of between 25,000 and 35,000 and was resistant to freeze/thawing procedures. The IFN activity was sensitive to trypsin and stable to low pH and heat. IFN with similar physical and biochemical properties was produced when ovine lentiviruses was added to control leukocyte cultures. IL-2 and PGE2 production and responses to mitogen by pulmonary lymph node lymphocytes of lentivirus-diseased lambs were not statistically different from control animals. Increased local production of IFN in lentivirus-infected host tissues may serve to accelerate the entry of leukocytes into virus-induced lesions promoting cell-mediated tissue damage and also provide increased numbers of cells for virus replication.

The thymus determines the spectrum of the receptor specificities of differentiating T cells for self-H-2; however, the phenotypic expression of T cell's specificity for self plus virus is determined predominantly by the H-2 type of the antigen presenting cells of the peripheral lymphoreticular system. Furthermore, virus specific helper T cells are essential for the generation of virus-specific cytotoxic T cells. For cooperation between mature T cells and other lymphocytes to be functional in chimeras, thymic epithelial cells and lymphohemopoietic stem cells must share the I region; killer T-cell generation also requires in addition compatibility for at least one K or D region. These conclusions derive from the following experiments: A leads to (A X B)F1 chimeric lymphocytes do produce virus-specific cytotoxic T-cell activity for infected A but not for infected B cells; when sensitized in an acutely irradiated and infected recipient (A X B)F1 these chimeric lymphocytes respond to both infected A and B. Therefore the predominantly immunogenically infected cells of chimeras the radiosensitive and by donor stem cells replaced lymphoreticular cells. In this adoptive priming model (KAIA/DB leads to KAIA/DC) chimeric lymphocytes could be sensitized in irradiated and infected F1 against KA and DC but not against infected DB targets. In contrast KBIB/DA leads to KCIC/DA chimeras' lymphocytes could not be sensitized at all in appropriately irradiated and infected F1 recipients. Thus these latter chimeras probably lack functional I-specific T helper cells that are essential for the generation of T killer cells against infected D compatible targets. If T cells learn in the thymus to recognize H-21 or K, D markers that are not at least partially carried themselves in other cells of the lymphoreticular system immunological interactions will be impossible and this paradox situation results in phenotypic immune incompetence in vivo.

LT-85 is an alveologenic adenocarcinoma of C3Hf/HeN mice. Comparisons of the in vitro and in vivo surface properties of these cells revealed that under normal conditions, they expressed I-A and I-E antigens iv vivo only. By using clonally derived cells, it was established that this phenomenon was not due to the selection of an Ia antigen-positive tumor cell subpopulation, but resulted from phenotypic conversion of Ia antigen-negative tumor cells. These tumor cells and 1053 cells (a fibrosarcoma of C3H/HeN MTV- mice) could, however, be induced to express I-A, I-E, and much higher levels of H-2 antigens in vitro by co-culturing them with spleen cells from LT-85 tumor-bearing C3H/HeN MTV- mice. In vitro induction of Ia and H-2 antigens did not result from contaminating splenocytes or from antigen transfer, because splenocytes from BALB/c (H-2d) mice immunized with A/J (H-2k/d) cells were able to induce the expression of Iak antigens by both tumor cell lines. It was found that this phenomenon was neither H-2-restricted nor antigen-specific. The results clearly indicated, however, that an immune response was required to generate phenotypic conversion of the tumor cells, both in vivo and in vitro. It was further found that soluble, rather than cellular, factors produced during an immune response induced the expression of Ia antigens by LT-85 and 1053 tumor cells. In contrast to what has been reported about the induction of Ia antigens on macrophages and normal epithelial and endothelial cells, the induction of Ia antigens on LT-85 and 1053 cells did not appear to require T cells, and did not involve gamma-interferon. These findings demonstrate that some tumor cells are capable of altering their MHC antigen phenotype in response to factors produced during an immune response in vivo or in vitro. Because of the involvement of Ia antigens in several aspects of immune phenomena, the ability of tumor cells to differentially express Ia antigens in response to environmental factors may have profound effects on host-tumor interactions. Furthermore, the differences seen in the phenotypes of tumor cells grown in vitro and in vivo suggest that in vitro methodologies of tumor cell characterization may not present a complete picture of the natural state of the tumor cell surface.

The H-2K glycoproteins were isolated from spleen cells of C3H/HeN and C3HfB/Hen mice and compared by tryptic peptide mapping techniques. The two antigens were found to be very similar in that more than 90 percent of detectable peptides appeared identical. However, two lysine-containing peptide present in tryptic digests of H-2K antigens isolated from C3H mice were absent from tryptic digests of H-2K antigens isolated from C3Hf mice. This was probably not the result of altered glucosylation since neuramindase digestion demonstrated that the disparate peptides were not glycopeptides but most probably resulted from substitution of one or two amino acids in the H-2K molecule of C3HfB/HeN mice. These differences were small but significant and demonstrated that H-2Kk (C3H) and H-2Kkv1 (C3Hf) antigens are structurally distinct. This is compatible with the observed reciprocal skin-graft rejection, MLR, and generation of cytotoxic T lymphocytes between the two strains. The significance of this finding in conjunction with what is known about properties of 1-ethyl-1-nitrosourea-induced tumors of C3Hf mice is discussed.