Genetic Association between H-2 Gene and Testosterone Metabolism in Mice

SEVERAL characters involved in sexual dimorphism or male reproductive performance are influenced by genetic factors that are linked with the histocompatibility-2 (H-2) system of the mouse. These factors influence sperm cell production and function^1–4 interstrain differences in relative weights of vesicular gland and testis^4,5, immune response to the male-specific histocompatibility antigen^6,7 and an androgen-dependent allotypic serum protein designated Slp⁸. Our finding of an H-2 linked gene influencing the size of such male hormone-dependent organs, as is the vesicular gland and testis, suggested that the amount of testosterone in plasma may be influenced by an H-2 linked gene. Whereas the genetic control of some hormonally determined traits is considered to be polygenic^9,10, other data indicate some endocrine variation is due to allelic substitution at a single locus or very few loci^11–14. These genes in the mouse genome have not yet been located.     

HLA‐DQ7 β1 and β2 derived peptides as immunomodulators

Modulation of protein–protein interactions involved in the immune system by using small molecular mimics of the contact interfaces may lead to the blockage of the autoimmune response and the development of drugs for immunotherapy. The nonpolymorphic β‐regions, exposed to the microenvironment, of the modeled HLA‐DQ7, which is genetically linked to autoimmune diseases, were determined. Peptides 132–141 and 58–67, located at the β₁ and β₂ domains of HLA‐DQ7, respectively, were tested for their involvement in the interactions with CD4⁺ T lymphocytes. Linear, cyclic, and dimeric analogs that mimic the exposed surfaces of HLA‐DQ7 were designed and synthesized. Their immunosuppressory activities, found in the secondary, humoral immune response to sheep erythrocytes (SRBC) in mice in vitro, ranged from 11% to 53%. The significance of the total charge of the peptides, the pattern of the hydrogen bonding, and the presence of secondary structure were investigated in relation to the immunomodulatory effect of the peptides. Two dimeric analogs of the HLA‐DQ7 58–67 fragment, consisting of the two monomers covalently linked by a polyethylene glycol (PEG) spacer, able to mimic the superdimers, were also synthesized and studied. As the 58–67 segment is located at the β₁ region of HLA‐DQ7, close to the major histocompatibility complex (MHC) groove, one may assume that the 58–67 peptide could accommodate the association between T‐cell receptor (TCR) and human leukocyte antigen (HLA) by activating a co‐stimulatory molecule of the TCR/HLA interaction. This hypothesis is supported by the confocal laser image of the fluorescein‐labeled 58–67 peptide and by the fact that it is an immunostimulator at low concentration. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.     

High MHC gene copy number maintains diversity despite homozygosity in a Critically Endangered single‐island endemic bird,but no evidence of MHC‐based mate choice

Small population sizes can, over time, put species at risk due to the loss of genetic variation and the deleterious effects of inbreeding. Losing diversity in the major histocompatibility complex (MHC) could be particularly harmful, given its key role in the immune system. Here, we assess MHC class I (MHC‐I) diversity and its effects on mate choice and survival in the Critically Endangered Raso lark Alauda razae, a species restricted to the 7 km² islet of Raso, Cape Verde, since ~1460, whose population size has dropped as low as 20 pairs. Exhaustively genotyping 122 individuals, we find no effect of MHC‐I genotype/diversity on mate choice or survival. However, we demonstrate that MHC‐I diversity has been maintained through extreme bottlenecks by retention of a high number of gene copies (at least 14), aided by cosegregation of multiple haplotypes comprising 2–8 linked MHC‐I loci. Within‐locus homozygosity is high, contributing to low population‐wide diversity. Conversely, each individual had comparably many alleles, 6–16 (average 11), and the large and divergent haplotypes occur at high frequency in the population, resulting in high within‐individual MHC‐I diversity. This functional immune gene diversity will be of critical importance for this highly threatened species’ adaptive potential.     

Peptide vaccines incorporating a ‘promiscuous’ T-cell epitope bypass certain haplotype restricted immune responses and provide broad spectrum immunogenicity

An ideal peptide vaccine should contain both B- and T-cell epitopes. Recognition of antigen by B cells is highly dependent on the three-dimensional conformation of the antigen whereas T cells recognize antigen only after it has been processed to release a peptide fragment which is bound to the major histocompatibility complex (MHC) class II molecule. However, T cells provide ‘help’ to B cells displaying the same processed, MHC-restricted from of the antigen, demonstrating that the T-cell response to a protein antigen is under genetic control. Thus, strategies for co-inclusion of T cell ‘helper’ epitopes with the B-cell determinant elicit immune responses that are in most cases genetically restricted to only one or a few alleles of the MHC with limited activity across divergent MHC class II haplotypes. This genetically restricted T cell stimulatory activity of peptides is a serious obstacle and consequently such constructs would be of limited practical value as a vaccine targeted to a majority of an outbred population. In the study described here, we have engineered tow peptides to encompass the sequences from the universally immunogenic tetanus toxoid (TT) epitope and the contraceptive vaccine candidate lactate dehydrogenase C₄ (LDH-C₄). We demonstrate the feasibility of using ‘promiscuous’ T-Cell epitopes colinearly constructed with a defined B-cell epitope to induce high titer antipeptide IgG antibodies specific for native protein antigen LDH-C₄ in several inbred strains of mice, outbred mice and rabbits. There appears to be a strong correlation between the capacity for the hybrid peptides to be stimulatory for the corresponding T cells in C57BL/6 (H-2^b) and C3H/HeJ (H-2^k) mice and their ability to be immunogenic. This correlation, however, appears to break down in H-2^d strains of mice since no antibodies were detected in BALB/c and barely detectable levels of antibodies in B10.D2 although activated T cells were detectable. Conversely, high titers of antipeptide antibodies are elicited in some strains (B10.BR) (H-2^k); C57BL/10 (H-2^k) without detectable IL-2 responses. Finally, we show that a determinant which was previously restricted to H-2^k can be rendered immunogenic in H-2^b with the ‘promiscuous’ TT epitope. Thus, certain haplotype-restricted immune responses can be bypassed, setting forth the ground work for the design of a universal vaccine by broadening the effective response in a larger number of individuals typically of the genetically diverse outbred human population.     

Bcl10 synergistically links CEACAM3 and TLR‐dependent inflammatory signalling

The neutrophil‐specific innate immune receptor CEACAM3 functions as a decoy to capture Gram‐negative pathogens, such as Neisseria gonorrhoeae, that exploit CEACAM family members to adhere to the epithelium. Bacterial binding to CEACAM3 results in their efficient engulfment and triggers activation of an nuclear factor kappa‐light‐chain‐enhancer of activated B cells (NF‐κB)‐dependent inflammatory response by human neutrophils. Herein, we report that CEACAM3 cross‐linking is not sufficient for induction of cytokine production and show that the inflammatory response induced by Neisseria gonorrhoeae infection is elicited by an integration of signals from CEACAM3 and toll‐like receptors. Using neutrophils from a human CEACAM‐expressing mouse line (CEABAC), we use a genetic approach to reveal a molecular bifurcation of the CEACAM3‐mediated antimicrobial and inflammatory responses. Ex vivo experiments with CEABAC‐Rac2^?/?, CEABAC‐Bcl10^?/?, and CEABAC‐Malt1^?/? neutrophils indicate that these effectors are not necessary for gonococcal engulfment, yet all 3 effectors contribute to CEACAM3‐mediated cytokine production. Interestingly, although Bcl10 and Malt1 are often inextricably linked, Bcl10 enabled synergy between toll‐like receptor 4 and CEACAM3, whereas Malt1 did not. Together, these findings reveal an integration of the specific innate immune receptor CEACAM3 into the network of more conventional pattern recognition receptors, providing a mechanism by which the innate immune system can unleash its response to a relentless pathogen.     

Preliminary evidence of genetic control of the immune response to the Thy-1.2 antigen in mice

The primary immune response to the Thy-1.2 antigen was measured by the plaque assay, detecting cells (PFC) producing antibodies lytic for thymocytes carrying this antigen. On the basis of statistically significant differences in response, the inbred strains studied could be classified as low (producing fewer than 10³ PFC/spleen) or high (producing more than 10³ PFC/spleen) responders. The data collected from these inbred strains and segregating generations were consistent with the concept that the primary immune response to the Thy-1.2 antigen is under genetic control. This control appeared to be exerted primarily by alleles at a locus linked to theH-2 complex but involvement of alleles at other loci could not be ruled out. Contrary to the commonly described experimental models, the high responsiveness to the Thy-1.2 antigen in some strain combinations seemed to be a recessive rather than a codominant trait.     

Altered Antigen Binding by Immunocompetent Cells as a Reflexion of Immunological History

AT least one of the cell types involved in the immune response has antigen specific receptors. This can be concluded from experiments in which specific immune responses have been dramatically affected by manipulations dependent on the ability of such cells to selectively bind to antigen. These manipulations include elimination of cells bearing a receptor of one specificity by passage through a column in which the homologous antigen is bound to particles¹; selective lethal irradiation of a sub-population of cells consequent to their ability to bind radioactively labelled antigen²; and separation of cells capable of forming rosettes by binding to foreign erythrocytes^3–4. We have used this latter technique to investigate whether the nature of the binding sites on cells necessary for the response to sheep erythrocytes in mice is influenced by the immunological history of the animal.     

Anti-θ Serum-indueed Suppression of the Cellular Transfer of Tumour-specific Immunity to a Syngeneic Plasma Cell Tumour

IT has been well documented that tumour-bearing mice can become resistant to their own tumours, especially with chemically induced fibrosarcomas^1–3 and the importance of cell-mediated immune responses rather than humoral antibody in the resistance to tumour transplants has been emphasized^3,4, although the exact mechanism of tumour cell destruction remains ill-defined. Studies in mice^5,6, using allogeneic tumour cells, have demonstrated that thymus-derived (T) lymphocytes are essential for the killing of tumour cells. In addition, using an in vitro method of immunization against histocompatibility antigens, tumour cell destruction either in vitro¹ or in vivo⁸ was shown to be due to T cells alone. In all of these latter studies, however, it is the strong H-2 histocompatibility antigens that are inducing the immune response and not the tumour-specific transplantation antigens (TSTA). We describe here a specific anti-TSTA response to a murine plasma cell tumour which can be transferred with lymphoid cells and which can be shown to involve the essential participation of T cells.     

Photo-induced joining of a transfer RNA with its cognate aminoacyl-transfer RNA synthetase

Formation of a stable linked complex of tyrosyl-tRNA synthetase with tRNA₁^tyr and with tRNA₂^tyr has been achieved by ultraviolet irradiation of the complex under mild solution conditions. The linking reaction is specific, as shown by a number of criteria. Sections of the nucleic acids that are joined to the enzyme have been identified by digesting the cross-linked complex with a specific nuclease. It is found that pieces of the helical dihydrouridine arm, of the anticodon loop, and of the extra loop are joined to the enzyme. No other sections are significantly linked to the protein.     

New Plasma Autoantigen and its Role in Autoimmune Disease of New Zealand Black Mice

THE New Zealand Black (NZB) strain of mice is an important experimental model for the study of autoimmune diseases¹. These mice are immunologically hyper-responsive to a number of antigens^2,3 and spontaneously initiate autoantibody responses to various autologous tissue antigens, including DNA and an erythrocyte antigen^1,3,4. The significance of anti-DNA⁵ and anti-murine leukaemia virus (MuLV)⁶ responses relative to the pathogenesis of the glomerulonephritis observed in this strain has been the subject of rather concerted inquiry and a proposed immune complex pathogenetic process has been substantiated^5–7. The anti-erythrocyte autoantibody response seems to be immunochemically and pathogenetically distinct^4,6.     

Reversible Blocking Effect of Anti-mouse Immunoglobulin Serum on the Induction of Immunity and Tolerance <Emphasis Type="Italic">in vitro</Emphasis>

THE induction of blast transformation by incubating lymphocytes with anti-immunoglobulin¹ and anti-allotype² sera has suggested that these cells have immunoglobulin on their surface. This hypothesis was directly verified by the demonstration of immunoglobulin on living mouse lymphoid cells by Raff et al.³. There is much evidence to indicate that immunocompetent cells have surface receptors for antigen. This idea is based on the finding that lymphocytes can bind radioactively labelled antigen to their surface^4,5 and that specific immune unresponsiveness occurs if lymphoid cells are exposed to either highly radioactive antigen⁶ or haptens capable of forming covalent bonds with proteins^7,8. The immunoglobulin nature of these antigen receptors is suggested by recent work showing that the binding of radioactively labelled antigen can be blocked by anti-immunoglobulin sera^5,9. Reports that the adoptive immune response of mouse spleen cells can be inhibited by anti-mouse immunoglobulin sera (AMS)^9,10 suggest that the interaction of antigen with the immunoglobulin receptor sites is a crucial step in the induction of the antibody response. We report here that the inhibitory action of AMS on the immune response is potentially reversible and that the induction of immune tolerance to polymerized flagellin (POL) in vitro may be blocked in the presence of AMS.     

THE CELLULAR IMMUNE RESPONSE OF DAPHNIA MAGNA UNDER HOST–PARASITE GENETIC VARIATION AND VARIATION IN INITIAL DOSE

In invertebrate–parasite systems, the likelihood of infection following parasite exposure is often dependent on the specific combination of host and parasite genotypes (termed genetic specificity). Genetic specificity can maintain diversity in host and parasite populations and is a major component of the Red Queen hypothesis. However, invertebrate immune systems are thought to only distinguish between broad classes of parasite. Using a natural host–parasite system with a well‐established pattern of genetic specificity, the crustacean Daphnia magna and its bacterial parasite Pasteuria ramosa, we found that only hosts from susceptible host–parasite genetic combinations mounted a cellular response following exposure to the parasite. These data are compatible with the hypothesis that genetic specificity is attributable to barrier defenses at the site of infection (the gut), and that the systemic immune response is general, reporting the number of parasite spores entering the hemocoel. Further supporting this, we found that larger cellular responses occurred at higher initial parasite doses. By studying the natural infection route, where parasites must pass barrier defenses before interacting with systemic immune responses, these data shed light on which components of invertebrate defense underlie genetic specificity.     

T‐cell epitope‐dependent immune response in inbred (C57BL/6J,SJL/J,and C3H/HeN) and transgenic P301S and Tg2576 mice

Alzheimer's disease is characterized by two pathological hallmarks, the intracellular deposition of hyperphosphorylated Tau protein and the extracellular deposition of Aβ_1–40/42, both being targets for immunotherapy. This study evaluates the immunogenic properties of three AD‐specific B‐cell epitopes (Tau_229–237[pT231/pS235], pyroGluAβ_3–8, and Aβ_{37/38–42/43}) linked to five foreign T‐cell epitopes (MVFP, TT, TBC Ag85B, PvT19, and PvT53) by immunizing inbred C57BL/6J (H‐2^b), SJL/J (H‐2^s2), and C3H/HeN (H‐2^k) mice. Two promising candidates with respect to MHC II restriction were selected, and two transgenic mouse models of AD, P301S (H‐2^b/k) and Tg2576 (H‐2^b/s) animals, were immunized with one B‐cell epitope in combination with two T‐cell epitopes. Responders displayed an enhanced immune response compared with wild‐type animals, which supports the vaccine design and the vaccination strategy. The immune response was also characterized by specific IgG subtype titers, which revealed a strong polarization toward the humoral pathway for immunization of phospho‐Tau, whereas for both Aβ vaccines, a mixed cellular/humoral pathway response was observed. Despite the diversity and unpredictability of the immunogenicity of the peptide vaccines, all three peptide vaccine formulations appear to be promising constructs for future evaluation of their therapeutic properties. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd.     

Interleukin-7, but Not Thymic Stromal Lymphopoietin,Plays a Key Role in the T Cell Response to Influenza A Virus

The immune response to viral infection is ideally rapid and specific, resulting in viral clearance and establishment of immune memory. Some viruses such as HIV can evade such responses leading to chronic infection, while others like Influenza A can elicit a severe inflammatory response with immune-related complications including death. Cytokines play a major role in shaping the appropriate outcomes to infection. While Interleukin-7 (IL-7) has a critical role in T and B cell development, treatment with IL-7 has recently been shown to aid the adaptive T cell response in clearance of chronic viral infection. In contrast, the IL-7-related cytokine thymic stromal lymphopoietin (TSLP) has a limited role in lymphocyte development but is important in the immune response to parasitic worms and allergens. The role for these cytokines in the immune response to an acute viral infection is unclear. IL-7 and TSLP share IL-7Rα as part of their heterodimeric receptors with the gamma common chain (γc) and TSLPR, respectively. We investigated the role of IL-7 and TSLP in the primary immune response to influenza A infection using hypomorphic IL-7Rα (IL-7Rα^449F) and TSLPR^−/− mice. We found that IL-7, but not TSLP, plays an important role in control of influenza A virus. We also showed that IL-7 signaling was necessary for the generation of a robust influenza A-specific CD4 and CD8 T cell response and that this requirement is intrinsic to CD8 T cells. These findings demonstrate a significant role for IL-7 during acute viral infection.     

Immune response to calf collagen type I in mice: A combined control ofIr-1A and nonH-2 linked genes

The genetically controlled immune response to calf skin collagen type I in mice could be demonstrated to be governed by at least two genes. One is linked to theH-2 complex and located within theIA subregion. High-responder alleles areH-2 ^b ,H-2 ^f , andH-2 ^s . The other gene(s) is not linked to theH-2 complex and high-responder allele(s) are found in the genome of B10 mice but not in the genome of DBA mice. There are strong indications that theIr-1A gene controls the response at the T-cell level, whereas it is assumed that the background gene(s) control the immune response at a different level.     

Genetic analysis of the non-H-2-linked Ir genes controlling the cytotoxic T-cell response to H-Y in H-2 d mice

The T-cell mediated immune responses to the male specific minor histocompatibility antigen H-Y in mice have been studied extensively as a model for immune responses to other weak antigens like tumor antigens or autoantigens. In a recent analysis of the strain distribution of the cytotoxic T-cell (Tc-cell) responsiveness to H-Y, it has been found that genes both within and outside the H-2 complex exert an interactive control. Whereas the H-2 ^b strains all are high responders, independent of their non-H-2 background, other H-2 haplotypes (d, k, and s) only allow for a response if they are combined with certain non-H-2 genes. The H-2-linked immune response genes (Ir-genes) have been previously mapped to the I and K or D region of the H-2 complex, but the mapping of the non-H-2 genes has not yet been established. In this study evidence is presented, using recombinant inbred strains and immunoglobulin heavy chain (Igh) congenic strains of mice, to show that there is more than one non-H-2 Ir-gene involved, that the main controlling genes are not linked to the Igh complex, and that at least one non-H-2 Ir-gene is linked to the H-3 region on chromosome 2. This region includes genes for beta-2-microglobulin (2m), the Ly-mllalloantigen a polymorphic cell surface glycoprotein (Pgp-1), a B-cell specific antigen Ly-4, a transplantation antigen H-3, and genes (Ir-2) controlling the immune response to Ea-1 and H-13.     

Lack of Anti-macrophage Species Specificity in Anti-lymphocytic Serum

THE mode of action of anti-lymphocytic serum (ALS) in suppressing cellular and humoral immune responses remains uncertain^1,2 although there is evidence that it acts preferentially on a sub-population of thymus derived small lymphocytes^3–5. Its action, however, is not confined to lymphocytes but it also affects neutrophils⁶, epithelial cells⁷ and macrophages^8–14. On the other hand, specific anti-macrophagic activity of ALS has been either questioned¹⁵ or refuted^16–18. Anti-neutrophil activity of ALS may be responsible for the anti-inflammatory properties of ALS¹⁹ which have been shown to be separate from its immuno-suppressive activity and not to prolong graft survival²⁰. Macrophages and monocytes, however, play an important role in the immune response²¹ and anti-macro phage activity might account for much of the immuno-suppressive capacity of ALS. Previous reports indicated that ALS was species but not strain specific with respect to both anti-lymphocytic⁸ and anti-macrophagic activity¹³. Species specificity of anti-lymphocytic activity is, however, not absolute^22,33,34; and this report demonstrates that the same is true for anti-macrophage activity, particularly between related species.     

Focus: Allergic Diseases and Type II Immunity: Intricate Relationship Between Adaptive and Innate Immune System in Allergic Contact Dermatitis

Allergic contact dermatitis (ACD) is a complex immunological allergic disease characterized by the interplay between the innate and adaptive immune system. Initially, the role of the innate immune system was believed to be confined to the initial sensitization phase, while adaptive immune reactions were linked with the advanced elicitation phase. However, recent data predicted a comparatively mixed and interdependent role of both immune systems throughout the disease progression. Therefore, the actual mechanisms of disease progression are more complex and interlinked. The aim of this review is to combine such findings that enhanced our understanding of the pathomechanisms of ACD. Here, we focused on the main cell types from both immune domains, which are involved in ACD, such as CD4⁺ and CD8⁺ T cells, B cells, neutrophils, and innate lymphoid cells (ILCs). Such insights can be useful for devising future therapeutic interventions for ACD.