MHC antigen induction by interferon gamma on cultured mouse pancreatic beta cells and macrophages. Genetic analysis of strain differences and discovery of an "occult" class I-like antigen in NOD/Lt mice.

This study provides a basis for understanding the wide variations reported in the literature in IFN-gamma inducibility of class II MHC antigens on murine beta cells. Inducibility is not an intrinsic property of all mouse beta cells, but instead depends upon strain- (and tissue-) specific response modifying factors. This was demonstrated by comparison of constitutive and IFN-gamma-induced class I and class II MHC gene products on cultured islet cell monolayers. Islet cultures were established from autoimmune diabetes-prone NOD/Lt mice, diabetes-resistant NON/Lt and CBA/J mice, as well as F1 hybrids between these latter two strains and NOD/Lt. Cultures of peritoneal macrophages (M phi) from each strain were established as controls. After 3 wk of culture (with incubation in the presence or absence of IFN-gamma during the last 6 d), constitutive expression as well as IFN-gamma induction of class I MHC antigen expression was demonstrated on NOD/Lt and NON/Lt islet cells by antibody plus complement-mediated cytotoxicity. Although CBA/J islets and M phi did not maintain constitutive class I or class II antigen expression in culture in the absence of IFN-gamma, class I H-2Kk antigen was IFN-gamma inducible. Whereas IFN-gamma-induced class II I-Ak antigen on CBA/J M phi, it failed to induce this antigen on CBA/J islets. In contrast, I-A antigens were IFN-gamma inducible on NOD/Lt and NON/Lt islets and M phi. In (CBA x NOD)F1 hybrids, loss of IFN-gamma inducibility of the I-ANOD product established that suppression was mediated by a trans-acting factor from the CBA/J genome. In the course of these studies, IFN-gamma inducibility of a crossreactive occult class I-like antigen on both NOD/Lt islet cell and M phi cultures was unexpectedly detected when mAb 28-13-3 (public specificity 39, reactive with H-2Kb,f) was used as a negative control. Although not detectable by cytofluorographic analysis of freshly isolated NOD/Lt splenic leukocytes, occult antigen could be induced on NOD/Lt peritoneal macrophages (M phi) cultured for 3 d in IFN-gamma. Time course of induction showed the occult antigen to be distinct from NOD/Lt class I and II gene products. In both islet cell and M phi cultures established from (CBA x NOD)F1 hybrids, trans-suppressive factor(s) from the CBA/J genome not only suppressed IFN-gamma-induced expression of I-ANOD, but additionally suppressed occult antigen induction. Backcross of F1 to both parental strains indicated that the occult locus was on Chr 17, tightly linked to MHC.(ABSTRACT TRUNCATED AT 400 WORDS)

NOD marrow stem cells adoptively transfer diabetes to resistant (NOD x NON)F1 mice.

Autoimmune beta-cell destruction occurred in otherwise diabetes-resistant F1 mice from an outcross between the nonobese diabetic (NOD) and nonobese normal (NON) inbred strains after adoptive transfer of hematopoietic stem cells from NOD donors. F1 mice were lethally irradiated and reconstituted with either NOD, NON, or F1 bone marrow. Only F1 mice reconstituted with NOD bone marrow developed hyperglycemia. The long (greater than or equal to 16-wk) prodromal period required for expression of overt diabetes contrasted with the rapidity (4-6 days) with which kidney-grafted F1 or NON islets (but not anterior pituitary) were eliminated from diabetic F1 mice. Thus, development of beta-cell-specific immunologic effectors was a chronic process, but once sufficient levels of autoimmunity were achieved, implanted beta-cells could be eliminated in an acute fashion. Thus, expression of NOD diabetogenic alleles in hematopoietic progenitor cells is sufficient for development of anti-beta-cell immunity. The elimination of grafted NON islets shows the effectors are capable of eliminating beta-cells from mice without the diabetogenic genotype.

Genetic control of diabetogenesis in NOD/Lt mice. Development and analysis of congenic stocks.

Genetic outcross and backcross analysis of nonobese diabetic (NOD/Lt) mice with a related but diabetes-resistant strain, nonobese normal (NON/Lt), has demonstrated that susceptibility to insulin-dependent diabetes mellitus is controlled in a recessive fashion by multiple genetic loci, including one (Idd-1s) associated with H-2 on chromosome 17 and another (Idd-2s) associated with Thy-1b/Apoa-1b (formerly Alp-1) on chromosome 9. To analyze the separate pathogenic contributions of Idd-1s and Idd-2s, two distinct congenic stocks of NOD/Lt mice homozygous on chromosomes 17 and 9 for NON/Lt linkage markers for the respective resistance alleles (Idd-1r and Idd-2r) were developed. The recessive nature of Idd-1s was confirmed at the fifth backcross generation in that 83% of females and 29% of males homozygous for NOD H-2 haplotype developed diabetes, whereas no diabetes occurred in any of the mice homozygous or heterozygous for the NON haplotype. However, codominant and recessive MHC-associated susceptibility genes in this congenic stock were indicated by the finding that at least one copy of the NOD/Lt MHC was required for insulitis development. Virtually no insulitis was detected in the pancreases of mice homozygous for NON haplotype at 42 wk of age, whereas heavy generalized insulitis was present in 3 of 19 H-2 heterozygotes and in 7 of 7 diabetic and 3 of 5 nondiabetic mice homozygous for NOD haplotype. Further indication of the presence of MHC-associated codominant and recessive MHC-associated susceptibility genes was the observation that the NOD MHC haplotype correlated in a codominant fashion with a relative increase in the percentage of splenic T-lymphocytes bearing the Ly-2 surface marker. Severe insulitis and concomitant high diabetes incidences occurred in all genotypic classes of congenic mice carrying Thy-1/Apoa-1 linkage markers for either NOD or NON alleles at Idd-2. Molecular analysis indicated that the NON-derived Idd-2r resistance allele had been replaced by recombination with Idd-2s from NOD. Restriction-fragment-length polymorphism analysis of two polymorphic markers proximal to Thy-1, low-density lipoprotein receptor Ldlr and Ets-1, a protooncogene, confirmed a recombinant chromosome 9, because homozygosity for NOD genomic fragments was found centromeric to an NON congenic segment of at least 20 centiMorgans spanning the Thy-1 and Mod-1 loci.(ABSTRACT TRUNCATED AT 400 WORDS)

Genetic and environmental control of diabetes induction by multi-dose streptozotocin in two BALB/c substrains.

BALB/cJ male mice were resistant and BALB/cByJ males were susceptible to induction of diabetes by multi-dose streptozotocin (MSz). Although both closely-related BALB/c substrains expressed H-2d haplotype, they could be differentiated by allelic differences at three genetic loci [Qa-2 (Chr 17), Bcd-1 (Chr 5), and Afr-1]. (BALB/cJ X BALB/cByJ)F1 males inherited the BALB/cJ resistance phenotype in a dominant fashion, thereby eliminating the BALB/cJ-expressed Afr-1b (recessive) allele as the susceptibility locus. Backcross of F1 mice to the susceptible BALB/cByJ strain produced a 1:1 segregation of susceptible and resistant (F1-like) phenotypes, suggesting that susceptibility was controlled by a single recessive gene. No linkage was found between the putative susceptibility gene and the mutant BALB/cByJ Qa-2,3 gene linked to the H-2 complex or with the mutant Bcd-1c allele. Since the resistant F1 males expressed low levels of androgen-dependent mouse urinary protein characteristic of the resistant BALB/cJ parental strain, the possibility was discussed that the alleles controlling sensitivity to MSz also controlled tissue sensitivity to endogenous androgens. An environmental effect on phenotype expression was indicated when BALB/cByJ males obtained from a colony free of pneumonia virus of mice (PVM) showed an attenuated rate of response to hyperglycemia induction in comparison to males obtained previously from an enzootically infected colony.

Increased expression of major histocompatibility complex antigens on lymphocytes from aged mice.

Many studies have reported age-related changes in immune responses that could be due to alterations in lymphoid cell numbers or functions. Here we report the results of studies using immunofluorescent staining and in vitro assays of cellular function to compare the expression of cell surface antigens on lymphocytes from mice up to 2 years of age. No significant changes were observed in the frequencies of spleen cells bearing class I or class II major histocompatibility complex (MHC) antigens, surface immunoglobulin, or Thy-1, Ly-1, Ly-2, or L3T4 antigens. However, the densities (per cell) of both class I and class II MHC antigens were increased significantly on cells from aged as compared to young mice, whereas the densities of the other cell surface antigens studied were unchanged or slightly decreased. The increased levels of MHC antigen expression in old relative to young mice were shown to be functionally significant regarding immunological stimulation. These data suggest that T-cell clones silent in young individuals may be activated in comparable situations in older animals, leading to immunological alterations perhaps including increased autoreactivity.