Bone Marrow Origin of Ia Molecules Purified from Epidermal Cells

Using radiation bone marrow chimeras, we have shown that Ia molecules purified from epidermal cell preparations of the mouse reflect the Ia phenotype of the bone marrow donor. This result strongly suggests that Ia molecules are synthesized by a bone-marrow-derived cell in epidermis. Furthermore, results of peptide map analysis of immunoprecipitated biosynthetically laveled Ia suggest that the Ia molecules found in skin are identical to those found B lymphocytes. These results support biochemical as well as serologic identity

Expression of la Antigens on T and B Cells and their Relationship to Immune-Response Functions

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73337/1/j.1600-065X.1976.tb00217.x.pd

Widespread transcription of a Qa region gene in adult mice

The mouse MHC class I family includes genes encoded in four regions: H- 2K, H-2D, Qa and Tla. While K/D genes are well characterized, relatively little is known about Qa or Tla genes. We have studied the transcription of a B10.P Qa region gene. DNA sequence comparisons of the transmembrane region, supported by Southern blot analysis of cosmid and genomic DNAs from BALB/c and C57BL/10, demonstrate the lambda 3a gene corresponds to Q4p. In both Northern blots and RNA protection experiments using probes derived from the 3' noncoding region, we found that Q4, like the H-2K and H-2D genes, is widely transcribed in B10.P tissues. These data demonstrate for the first time widespread transcription of a Qa gene

CD4−CD8− T cells control intracellular bacterial infections both in vitro and in vivo

Memory T cells, including the well-known CD4+ and CD8+ T cells, are central components of the acquired immune system and are the basis for successful vaccination. After infection, CD4+ and CD8+ T cells expand into effector cells, and then differentiate into long-lived memory cells. We show that a rare population of CD4−CD8−CD3+αβ+γδ−NK1.1− T cells has similar functions. These cells potently and specifically inhibit the growth of the intracellular bacteria Mycobacterium tuberculosis (M. tb.) or Francisella tularensis Live Vaccine Strain (LVS) in macrophages in vitro, promote survival of mice infected with these organisms in vivo, and adoptively transfer immunity to F. tularensis LVS. Furthermore, these cells expand in the spleens of mice infected with M. tb. or F. tularensis LVS, and then acquire a memory cell phenotype. Thus, CD4−CD8− T cells have a role in the control of intracellular infection and may contribute to successful vaccination

The relationship of the major murine histocompatibility region associated IA antigens to mitogen responses

Genes located in the I region of the H-2 complex control a system of lymphocyte alloantigens (Ia) which are expressed on subpopulations of T and B cells. Specific anti-Ia serum plus rabbit complement removed the B-lymphocyte population responsive to the mitogen LPS and the subpopulation of T cells responsive to Con-A. Lymphocytes sensitive to PHA or leucoagglutinin were not removed by anti-Ia serum and complement. Significant inhibition of the proliferative response to LPS was also obtained by brief periods of cell pretreatment with anti-Ia antibodies without complement. This inhibition was specific with the appropriate anti-Ia serum and did not occur with anti-H-2K sera or when cells of a different I region were pretreated.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/21764/1/0000158.pd

Mouse genetic locus Lps influences susceptibility to Neisseria meningitidis infection.

We surveyed a number of inbred mouse strains for susceptibility to meningococcemia. Mice of all strains became bacteremic after intraperitoneal injection of a serogroup C, serotype 2a human disease isolate, but the strains differed in levels of bacteremia, indicating influences of the host genome on susceptibility. There was no significant correlation between level of bacteremia and differences at major histocompatibility or immunoglobulin loci; the Salmonella susceptibility locus, Ity; the complement C5 locus, Hc; the antibody response locus, xid; or the transferrin locus, Trf. However, the Lps locus, which influences a range of host cellular responses to endotoxin and affects susceptibility to Salmonella typhimurium, did influence susceptibility to meningococcemia. There were significant differences in levels of bacteremia between C3H/HeJ (Lpsd) mice and each of the other strains (all Lpsn). We confirmed the association of the Lpsd genotype with susceptibility by using coisogenic strains from two widely separated mouse lineages: C3H and B10. Lpsd mice experienced a 1,000-fold proliferation of bacteria and were bacteremic for days before clearing the infection. In contrast, Lpsn mice cleared the bacteremia in less than 1 day. There was no difference in meningococcal growth in vitro in serum from C3H/HeJ and coisogenic C3H/HeN (Lpsn) mice, suggesting that the Lps-related difference in susceptibility may involve a cellular response

Virus-specific, CD8+ major histocompatibility complex class I-restricted cytotoxic T lymphocytes in lymphocytic choriomeningitis virus-infected beta2-microglobulin-deficient mice.

Following infection with lymphocytic choriomeningitis virus (LCMV), normal adult mice generate virus-specific, major histocompatibility complex (MHC) class I-restricted cytotoxic T lymphocytes (CTL) which clear the virus after intraperitoneal infection or cause death following intracranial (i.c.) infection. We have investigated the response of beta2-microglobulin-deficient (beta2m-) mice of the H-2d haplotype (KOD mice) to LCMV infection. Unlike H-2b beta2m- mice, which generate CD4+ MHC class II-restricted CTL in response to LCMV, KOD mice generate high levels of CD8+ MHC class I-restricted, virus-specific CTL. These CTL are specific for the LCMV nucleoprotein epitope (residues 118 to 126) in association with the Ld class I molecule, analogous to the CTL response in wild-type mice. KOD mice are also susceptible to lethal LCM disease, with 75 to 80% of the mice dying 7 to 9 days following i.c. infection with virus. Similar to results with normal mice, lethal LCM disease in KOD mice is prevented by in vivo depletion of CD8+ T cells prior to i.c. infection. In contrast to wild-type mice, however, KOD mice cannot control LCMV and become persistently infected. Overall, these results demonstrate that beta2m is not an absolute requirement for presentation of endogenous antigen on Ld or for induction of virus-specific Ld-restricted CTL in vivo

The LCMV gp33-specific memory T cell repertoire narrows with age

Abstract Background The memory response to LCMV in mice persists for months to years with only a small decrease in the number of epitope specific CD8 T cells. This long persistence is associated with resistance to lethal LCMV disease. In contrast to studies focused on the number and surface phenotype of the memory cells, relatively little attention has been paid to the diversity of TCR usage in these cells. CD8+ T cell responses with only a few clones of identical specificity are believed to be relatively ineffective, presumably due to the relative ease of virus escape. Thus, a broad polyclonal response is associated with an effective anti-viral CD8+ T cell response. Results In this paper we show that the primary CD8+ T cell response to the LCMV gp33-41 epitope is extremely diverse. Over time while the response remains robust in terms of the number of gp33-tetramer+ T cells, the diversity of the response becomes less so. Strikingly, by 26 months after infection the response is dominated by a small number TCRβ sequences. In addition, it is of note the gp33 specific CD8+ T cells sorted by high and low tetramer binding populations 15 and 22 months after infection. High and low tetramer binding cells had equivalent diversity and were dominated by a small number of clones regardless of the time tested. A similar restricted distribution was seen in NP396 specific CD8+ T cells 26 months after infection. The identical TCRVβ sequences were found in both the tetramerhi and tetramerlo binding populations. Finally, we saw no evidence of public clones in the gp33-specific response. No CDR3 sequences were found in more than one mouse. Conclusions These data show that following LCMV infection the CD8+ gp33-specific CD8 T cell response becomes highly restricted with enormous narrowing of the diversity. This narrowing of the repertoire could contribute to the progressively ineffective immune response seen in aging

The distribution of la antigens of the H-2 complex on lymph node cells by immunoferritin labelling

The distribution of Ia antigens on the surfaces of lymph node lymphocytes of several mouse strains was investigated using indirect immunoferritin labeling and electron microscopy. The immunoferritin labeling results agreed with results of cytotoxic tests in strain distribution of reactivity, proportion of cells showing label, and cell populations reacting. Capping was induced by increased incubation temperature but conditions for Ia antigen mobilization varied somewhat between the two anti-Ia antisera employed. Uncapped specimens generally showed a denser, more evenly distributed antigen coating than is the case for H-2 antigens labeled by the same indirect immunoferritin method.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22111/1/0000538.pd

The Structural Basis for the Increased Immunogenicity of Two HIV-Reverse Transcriptase Peptide Variant/Class I Major Histocompatibility Complexes

Designing altered peptide ligands to generate specific immunological reactivity when bound to class I major histocompatibility complexes is important for both therapeutic and prophylactic reasons. We have previously shown that two altered peptides, derived from human immunodeficiency virus (HIV)-reverse transcriptase (RT) residues 309-317, are more immunogenic in vitro than the wild-type peptide. One peptide variant, I1Y, was able to stimulate RT-specific cytotoxic T cells from the blood of three HIV-infected individuals better than the wild-type RT peptide. Both I1Y and I1F peptide variants increase the cell surface half-life of the peptide-class I complex approximately 3-fold over that of the RT peptide but have different immunological activities. These peptides are candidates for the design of vaccines for HIV due to their increased immunogenicity. To understand the basis for the increased cell surface stability compared with wild-type peptide and to understand the differences in T cell recognition between I1Y and I1F, we determined the x-ray crystal structures of the two class I MHC-peptide complexes. These structures indicate that the increased cell surface half-life is due to pi-pi stacking interactions between Trp-167 of HLA-A2.1 and the aromatic P1 residues of I1F and I1Y. Comparison of the structures and modeling potential T cell receptor (TCR) interactions suggests that T cell interactions and immunogenicity are different between I1Y and I1F for two reasons. First, subtle changes in the steric and polar properties of the I1Y peptide affect TCR engagement. Second, water-mediated hydrogen bond interactions between the P1-Tyr and the P4-Glu peptide residues increase peptide side chain rigidity of residues critical for TCR engagement