Genetic control of susceptibility to experimental Lyme arthritis is polygenic and exhibits consistent linkage to multiple loci on chromosome 5 in four independent mouse crosses.

C3H/He mice infected with Borrelia burgdorferi develop severe arthritis and are high antibody responders, while infected C57BL/6 and BALB/c mice develop mild arthritis and less robust humoral responses. Genetic analysis using composite interval mapping (CIM) on reciprocal backcross populations derived from C3H/HeN and C57BL/6N or C3H/HeJ and BALB/cAnN mice identified 12 new quantitative trait loci (QTL) linked to 10 murine Lyme disease phenotypes. These QTL reside on chromosomes 1, 2, 4, 6, 7, 9, 10, 12, 14, 15, 16, and 17. A reanalysis of an F(2) intercross between C57BL/6N and C3H/HeN mice using CIM identified two new QTL on chromosomes 4 and 15 and confirmed the location of seven previously identified loci. Two or more experimental crosses independently verified six QTL controlling phenotypes after B. burgdorferi infection. Additionally, Bb2 on chromosome 5 was reproduced in four experimental populations and was linked to the candidate locus Cora1. Evidence of four distinct QTL residing within the 30-cM region of chromosome 5 encompassing the previously mapped Bb2 and Bb3 loci was shown by CIM. Interestingly, some alleles contributing to susceptibility to Lyme arthritis were derived from C57BL/6N and BALB/cAnN mice, showing that disease-resistant strains harbor susceptibility alleles.

Neuroendocrine regulation of sexually dimorphic brain structure and associated sexual behavior in male rats is genetically controlled.

Steroid hormones, particularly 17beta-estradiol (E2), regulate the development and expression of neural structures and sexual behavior. Recently, we demonstrated that E2-regulated responses are controlled by quantitative trait loci. In this study, we quantified 1) volume of the sexually dimorphic nucleus (SDN) of the preoptic area (POA); 2) medial basal hypothalamic (MBH)-POA aromatase and 5alpha-reductase enzyme activities during prenatal development and in adults; 3) serum LH, testosterone, FSH, E2, prolactin (PRL), and corticosterone levels; 4) reproductive organ (i.e., testis and ventral prostate) weights; and 5) male mating behavior in Noble (NB/Cr) and Wistar-Furth (WF/NCr) rat strains to determine the genetic influence on the measured parameters. Maximal phenotypic divergence in male SDN-POA volumes was seen between NB/Cr versus WF/NCr and BDIX/Cr rats (among nine rat strains initially examined), with the average SDN-POA volume of NB/Cr male rats being significantly greater ( approximately 30%) than that of either WF/NCr or BDIX/Cr males. Subsequent experiments investigated WF/NCr versus NB/Cr male rats in further detail. Significantly higher MBH-POA aromatase activity was seen in adult WF/NCr versus NB/Cr males, while MBH-POA 5alpha-reductase rates were not significantly different (within or between sex) for the two rat strains assayed. Serum LH levels were significantly higher (by greater than sixfold) in WF/NCr versus NB/Cr males, whereas testis organ:body weight and ventral prostate:body weight ratios in WF/NCr versus NB/Cr males were significantly smaller (by approximately 6-fold for testis and approximately 1.5-fold for prostate values). Serum FSH levels were significantly higher (by twofold) in WF/NCr versus NB/Cr males. However, serum testosterone levels were not significantly different, whereas E2 levels were approximately twofold higher (but not significantly different) in WF/NCr versus NB/Cr animals. No significant differences were found in basal (i.e., nonstress) serum PRL or corticosterone levels between the WF/NCr and NB/Cr males. In male copulatory tests, NB/Cr males exhibited significantly more aggressive sexual behavior (e.g., in mounting, intromission, and ejaculation parameters) compared with WF/NCr males. Taken together, these findings indicate that WF/NCr males are, in general, low responders, whereas NB/Cr males are high responders to hormonal signals. The obtained data suggest that the correlative, phenotypic variation in SDN-POA volume (i.e., structure) and reproductive hormone patterns and mating behavior (i.e., function) of WF/NCr versus NB/Cr males is regulated by potentially E2-mediated mechanisms that are genetically controlled.

Normal development of thymus in male and female mice requires estrogen/estrogen receptor-alpha signaling pathway.

Estrogen receptors (ERs) are expressed in the thymus of both males and females, but their role in thymic development and function is unclear. To determine whether ERalpha plays a role in thymic function of either males or females, we compared thymuses of male and female wild-type (WT) and ERalpha knockout (alphaERKO) mice from birth to adulthood. Although thymic size was similar in both male and female WT and alphaERKO mice at birth (d 0), by postnatal d 5 and at all subsequent ages, both male and female alphaERKO mice had significant (30-55%) reductions in thymic weight. Morphometric analysis revealed a reduction in thymic medullary areas in adult alphaERKO mice compared with age-matched WT controls that paralleled thymic involution. There were changes in relative percentages of CD4+ and CD4+CD8+ T-cells, and large decreases (70-80%) in overall absolute numbers of CD4+ and CD4+CD8+ T-cells. Serum corticosterone and testosterone levels were not different in either neonatal or adult male WT or alphaERKO mice, and serum levels of 17beta-estradiol (E2) were similar in neonatal WT and alphaERKO males, indicating that increases in these thymolytic hormones are not responsible for the decreased thymic weight in alphaERKO males. Additionally, delayed-type hypersensitivity was significantly increased in male alphaERKO mice compared with WT mice. In summary, ERalpha deficiency does not inhibit initial differentiation or fetal thymic development, but the absence of ERalpha results in marked decreases in thymic size in both sexes during the postnatal period. These results are the first direct demonstration that the E2/ERalpha signaling system is necessary for maintenance of normal postnatal function of the female thymus gland. The similar results obtained in males demonstrate a role for the E2/ERalpha signaling system in the male thymus and emphasize that estrogens play a more critical role in the male than previously realized.

The development of male reproductive organ abnormalities after neonatal exposure to tamoxifen is genetically determined.

Responses of the male reproductive organs to neonatal exposures of tamoxifen (Tx) were examined in seven different strains of mice (A/J, AKR/J, BALB/cAnN, C3H/HeJ, C57BL/6J, DBA/ 2J, and FVB/N). Male mice were given daily subcutaneous injections of 2 microg Tx from postnatal day 1 to 5, and the testes, epididymides, ductus deferens, and seminal vesicles were examined at 3 months of age. At necropsy, the testes and seminal vesicles of Tx-treated groups were significantly smaller in size than those of the control groups in all strains. Histologically, the testes of AKR/J, BALB/cAnN, and FVB/N mice showed no abnormality after neonatal treatment with Tx. In contrast, the testes of A/J, C3H/HeJ, C57BL/6J, and DBA/ 2J mice were often necrotic and highly disorganized, with severe inflammation. In the connective tissue surrounding these testes, relatively large arteries were involved in the inflammation, and the vascular lumen was occluded by the thickened tunica interna, suggesting that these testicular changes were due to infarction. Similarly, the epididymides and ductus deferens of Tx-treated A/J, C3H/HeJ, C57BL/6J, DBA/2J, and FVB/N mice showed chronic pyogranulomatous inflammation. The epithelium of the seminal vesicles of Tx-treated A/J, C3H/HeJ, C57BU6J, DBA/2J, and FVB/N mice also exhibited moderate hyperplasia, with squamous metaplasia. These results indicate that neonatal exposure to Tx causes various abnormalities of the male reproductive organs in postpubertal mice, depending on the strains, and suggest that a genetic component plays a major role in determining the phenotypic variation observed.

Dual role of interleukin-10 in murine Lyme disease: regulation of arthritis severity and host defense.

In the murine model of Lyme disease, C3H/He mice exhibit severe arthritis while C57BL/6N mice exhibit mild lesions when infected with Borrelia burgdorferi. Joint tissues from these two strains of mice harbor similar concentrations of B. burgdorferi, suggesting that the difference in disease severity reflects differences in the magnitude of the inflammatory response to B. burgdorferi lipoproteins. Stimulation of bone marrow macrophages from C3H/HeN mice with the B. burgdorferi lipoprotein OspA resulted in higher-level production of the inflammatory mediators tumor necrosis factor alpha, nitric oxide, and interleukin-6 (IL-6) than that of macrophages from C57BL/6N mice. In contrast, macrophages from C57BL/6N mice consistently produced larger amounts of the anti-inflammatory cytokine IL-10 than did C3H/HeN macrophages. Addition of recombinant IL-10 suppressed the production of inflammatory mediators by macrophages from both strains. IL-10 was found to modulate B. burgdorferi-induced inflammation in vivo, since C57BL/6J mice deficient in IL-10 (IL-10-/-) developed more severe arthritis than wild-type C57BL/6J mice. The increase in arthritis severity was associated with a 10-fold decrease in the number of B. burgdorferi organisms present in ankle tissues from IL-10-/- mice. These findings suggest that in C57BL/6 mice, IL-10-dependent regulation of arthritis severity occurs at the expense of effective control of bacterial numbers.

Physical mapping of the autoimmune disease susceptibility locus, Bphs: co-localization with a cluster of genes from the TNF receptor superfamily on mouse chromosome 6.

An important approach to understanding complex diseases is to reduce them into well-characterized subphenotypes that are under monogenic control. One such example is Bordetella pertussis toxin-induced histamine sensitization in mice, a subphenotype of experimental allergic encephalomyelitis and experimental allergic orchitis. This subphenotype is controlled by a single locus, Bphs, previously mapped to a 33 cM region on mouse Chromosome (Chr) 6. We achieved considerable reduction of this candidate region and constructed a YAC contig across the refined interval. Our results demonstrate that Bphs is located between D6Mit151 and a newly developed marker, EC108RR, a region containing a small cluster of genes belonging to the TNF receptor superfamily. Sequence and quantitative analysis of the candidate gene, tumor necrosis factor receptor 1 (Tnfr1, p55), indicates that it is unlikely to be Bphs. However, the location of Bphs, together with physiologic effects it shares with Tnfr1 activation, suggest that Bphs may prove to be another member of the TNF receptor superfamily.

Interacting quantitative trait loci control phenotypic variation in murine estradiol-regulated responses.

The steroid hormone estradiol (E2) elicits a spectrum of systemic and uterotropic responses in vivo. For example, E2 treatment of ovariectomized adult and sexually immature rodents leads to uterine leukocytic infiltration, cell proliferation, and organ growth. E2-regulated growth is also associated with a variety of normal and pathological phenotypes. Historically, the uterine growth response has been used as the key model to understand the molecular and biochemical mechanisms underlying E2-dependent growth. In this study, genome exclusion mapping identified two quantitative trait loci (QTL) in the mouse, Est2 and Est3 on chromosomes 5 and 11, respectively, that control the phenotypic variation in uterine wet weight. Both QTL are linked to a variety of E2-regulated genes, suggesting that they may represent loci within conserved gene complexes that play fundamental roles in mediating the effects of E2. Interaction and multiple trait analyses using the uterine leukocyte response and wet weight suggest that Est4, a QTL on chromosome 10, may encode an interacting factor that influences the quantitative variation in both responses. Our results show that E2-dependent responses can be genetically controlled and that a genetic basis may underlie the variation observed in many E2-dependent phenotypes.

Molecular analysis of the major MHC recombinational hot spot located within the G7c gene of the murine class III region that is involved in disease susceptibility.

Recombination within the MHC does not occur at random, but crossovers are clustered in hot spots. We previously described a recombinational hotspot within the 50-kb Hsp70.3-G7 interval in the class III region of the mouse MHC. The parental haplotypes of recombinants with crossovers in this region represent the majority of the laboratory haplotypes (a, b, d, dx, k, m, p, px, q, s, and u). Using microsatellite markers and sequence-based nucleotide polymorphisms, the breakpoint intervals of 30 recombinants were mapped to a 5-kb-long interval within the G7c gene adjacent to G7a. Recombination within the G7c hot spot does not appear to be restricted to certain haplotypes. Sequence motifs that had been suggested to be associated with site-restricted meiotic recombination were absent in the vicinity of the G7c hot spot, and hence, these sequence motifs are no prerequisite for meiotic recombination. The G7c hot spot resides in a region to which a number of disease susceptibility loci have been mapped, including susceptibility to cleft palate, experimental autoimmune allergic orchitis, and chemically induced alveolar lung tumors. The exact localization of crossovers in recombinants that have been used in functional studies is important for mapping susceptibility genes and limits the number of candidate genes.

Evidence for the genetic control of estradiol-regulated responses. Implications for variation in normal and pathological hormone-dependent phenotypes.

The ovarian steroid hormone estrogen (E2) elicits a multiplicity of both systemic and uterotropic responses in vivo. For example, the administration of E2 to ovariectomized (Ovx) and sexually immature rodents leads to uterine-specific inflammatory infiltrates. In this study, we quantitated the number of eosinophils and BM8+, Ia+, and CD4+ cells in uteri obtained from adult Ovx control and E2-treated C57BL/6J, C3H/HeJ, and (C57BL/6J x C3H/HeJ) (B6C3) F1 hybrid mice. All three strains exhibited a significant increase in the number of uterine eosinophils and BM8+ macrophages after E2 treatment. However, C57BL/6J and B6C3 F1 hybrid mice responded with a greater number of infiltrating eosinophils and macrophages as compared with C3H/HeJ. A similar analysis of Ia+ and CD4+ cells showed that E2 treatment either down-regulates or does not affect the number of such cells in all three strains. Genome exclusion mapping using a (C57BL/6J x C3H/HeJ) x C3H/HeJ backcross population localized Est1, the major locus controlling the number of eosinophils infiltrating the uterus after E2 treatment, to chromosome 4. In addition, suggestive linkage to marker loci on chromosomes 10 and 16 was detected and evidence for locus interaction is presented. Our results conclusively demonstrate that E2-regulated/ dependent responses can be genetically controlled, indicating that the phenotypic variation observed in both the normal and pathological effects of E2 may, in part, be due to a genetic component.

Disproportionate micromelia (Dmm) in mice caused by a mutation in the C-propeptide coding region of Col2a1.

Mice that are homozygous for the autosomal semidominant disproportionate micromelia (Dmm) mutation are characterized by disproportionate micromelia, thoracic dysplasia, and cleft palate. Chondrocytes of the epiphyseal growth plates are not organized into columns, and ultrastructural analysis reveals excessive dilation of the endoplasmic reticulum and a paucity of collagen fibrils in the extracellular matrix. To map the Dmm locus, Dmm mice were crossed with the multiple ecotropic viral (MEV) linkage testing stock. Significant linkage of Dmm to the fourteen MEV linkage markers was not observed, thereby excluding approximately 50% of the genome as candidate regions encoding Dmm. Subsequently, microsatellite markers were used to assess linkage to the nonexcluded regions of the genome, revealing tight linkage to the locus of Col2a1, the gene encoding the alpha-chains of type II collagen. alpha 1(II) collagen cDNA, synthesized with RNA from homozygotes, was cloned and sequenced, revealing a three-nucleotide deletion in the region encoding the C-propeptide globular domain. The deletion leads to the substitution of one amino acid, Asn, in the mutant for two amino acids, Lys and Thr, in the wild type. Several human chondrodysplasias with similar phenotypes to that of Dmm are associated with defects in type II collagen. Thus, mice bearing the Dmm mutation serve as a model for studying the pathogenesis of these disorders while revealing novel insights into normal skeletal morphogenesis.

Multiple loci govern the bone marrow-derived immunoregulatory mechanism controlling dominant resistance to autoimmune orchitis.

The existence of immunoregulatory genes conferring dominant resistance to autoimmunity is well documented. In an effort to better understand the nature and mechanisms of action of these genes, we utilized the murine model of autoimmune orchitis as a prototype. When the orchitis-resistant strain DBA/2J is crossed with the orchitis-susceptible strain BALB/cByJ, the F1 hybrid is completely resistant to the disease. By using reciprocal radiation bone marrow chimeras, the functional component mediating this resistance was mapped to the bone marrow-derived compartment. Resistance is not a function of either low-dose irradiation- or cyclophosphamide (20 mg/kg)-sensitive immunoregulatory cells, but can be adoptively transferred by primed splenocytes. Genome exclusion mapping identified three loci controlling the resistant phenotype. Orch3 maps to chromosome 11, whereas Orch4 and Orch5 map to the telomeric and centromeric regions of chromosome 1, respectively. All three genes are linked to a number of immunologically relevant candidate loci. Most significant, however, is the linkage of Orch3 to Idd4 and Orch5 to Idd5, two susceptibility genes which play a role in autoimmune insulin-dependent type 1 diabetes mellitus in the nonobese diabetic mouse.

Mechanisms of autoimmune disease in the testis and ovary.

This article reviews recent research on autoimmune diseases of the testis and ovary based on two experimental approaches for induction of autoimmune diseases of the gonads (immunization with testis or ovary antigen, usually with adjuvant, and deliberate alteration of the immune system in normal animals, without injecting antigen or adjuvant). It has been found that the local testicular immunoregulatory environment partially impedes autoimmune responses to ontogenic testis antigens and regulatory T cells usually control pathogenic T cells that are found in the normal peripheral immune system. If the clonal balance of these CD4+ T cell subsets is tipped in favour of pathogenic T cells, autoimmune diseases of the gonads could ensue. Loss of regulatory T cells may occur through aberrant T cell development, or oophoritogenic T cells can be activated by non-ovarian peptides that crossreact with self peptides at the level of the T cell receptor. The inflammatory CD4 (Th1) T cell mechanism has been established to be a critical pathway for autoimmune orchitis and autoimmune oophoritis; tumour necrosis factor has been shown to be required for amplification of the pathogenic T cell response. Histopathology has suggested tissue locations wherein pathogenic T cells encounter testicular and ovarian target antigens. Antibodies bind to both testicular and ovarian target antigens during the development of autoimmune orchitis and autoimmune oophoritis, but the precise role of the antibodies has not been determined. Resolution of this role may influence the clarification of the mechanism whereby autoantibody may access ejaculated human spermatozoa to cause infertility and the future of contraceptive vaccine development based on ovarian antigens. A novel mechanism of autoantibody induction and an immunogenetic approach to autoimmune oophoritis and orchitis, based on molecular linkage analysis of inbred mice, are also reviewed.

Induced regression of bovine papillomas by intralesional immunotherapy.

It has long been assumed that papilloma regression is mediated by immunological mechanisms which are probably cellular in nature. The potentiation of these responses may alter the course of papilloma progression. Certain strains of the bacterium Corynebacterium parvum (Propionibacterium acnes) have been shown to augment cellular immune mechanisms by increasing both macrophage and natural killer cell activity. This study involves the use of naturally occurring bovine papillomas to investigate the immune mechanisms involved in induced papilloma regression. Papillomas were treated by intralesional injection of a C. parvum suspension. Treated papillomas were biopsied at various stages of regression. Tissue samples were subjected to immunohistochemical staining to identify specific infiltrating cells. Results showed that intralesional administration of C. parvum was capable of inducing regression of bovine papillomas in 8-15 weeks. Immunological staining revealed that regression was associated with an increased number of CD8+ and gamma delta+ cells in the dermis, as well as a marked infiltration of neutrophils.

Role of mast cells in early epithelial target cell injury in experimental acute graft-versus-host disease.

The skin is a major target organ for graft-versus-host disease (GVHD), the principal complication of allogeneic bone marrow transplantation. The purpose of the present study was to test whether mast cell degranulation might be related to early target cell injury in the development of acute GVHD. We employed two irradiated murine strain combinations, one in which disease was mediated by CD4+ effector T cells (B10.D2-->DBA/2), and the other by CD8+ effector T cells (B10.BR-->CBA). As compared to controls, both models exhibited mast cell degranulation of differing extents and patterns, as well as dyskeratosis in the epidermis before the influx of effector lymphocytes. These results suggested that factors produced and released by degranulated dermal mast cells might contribute to early target cell injury. Accordingly, the possible role of tumor necrosis factor (TNF)-alpha, a cytokine recently discovered in mast cell granules, was investigated by the injection of anti-TNF-alpha antibody during the course of disease mediated by either CD4+ or CD8+ T cells. Although overall survival of recipients undergoing CD4+ T-cell-mediated GVHD was only slightly improved and the extent of mast cell degranulation was not affected by anti-TNF-alpha antibody treatment, the skin exhibited a significant diminution in the number of dyskeratotic cells/linear mm at 3-4 weeks post-transplantation. In contrast, anti-TNF-alpha antibody failed to enhance survival or reduce the number of dyskeratotic cells in the skin during CD8+ T-cell-mediated disease. Finally, to determine whether CD8+ T-cell-mediated GVHD was at all dependent upon mast cell involvement, the C3H.SW-->B6WWv strain combination was utilized, in which recipients were genetically deficient in mast cells. Onset of GVHD was significantly delayed in B6WWv mice and was clearly correlated to the appearance and increase of de novo mast cells at later time points.

Glucocorticoid and progestin regulation of eosinophil chemotactic factor and complement C3 in the estrogen-treated rat uterus.

To study the steroid regulation of estradiol-induced uterine eosinophil chemotactic factor activity (ECF-U) in the rat, we injected immature female rats with combinations of estradiol, dexamethasone, progesterone, and the antihormones RU-486 and ketoconazole. An in vitro chemotactic system using blind well chambers and employing eosinophil-differentiated HL-60 promyelocytic cells was used as a bioassay for ECF-U activity. Dexamethasone and progesterone both antagonized the effects of estradiol on stimulation of ECF-U activity; neither hormone induced ECF-U activity when given alone. RU-486 and ketoconazole were able to block the inhibitory effects of dexamethasone and progesterone. The effects of dexamethasone and progesterone appear to be mediated through their specific nuclear receptors and are not due to direct effects on the chemotactic cell. Comparison of the steroid regulation of ECF-U activity with the estradiol-induced synthesis and secretion of complement component C3 showed that progesterone antagonized the effects of estradiol in both systems, whereas dexamethasone was antagonistic on ECF-U, but not on the secretion of C3. Taken together these results suggest that estradiol's effects in the rat uterus may be modulated by other steroids in at least two systems, bringing into question the common practice of studying uterine steroid actions by evaluation of a single protein or mRNA.

Progesterone regulation of estradiol-induced rat uterine secretory protein, complement C3.

Previously, using DNA sequencing, Northern and Southern analysis, and immunohistochemical data, we identified an estrogen-stimulated secretory protein as the third component of complement (C3). In this study, we demonstrate that progesterone modulated the estradiol regulation of C3 in immature rats as well as during the normal reproductive cycle. C3 was most abundant during estrus and reached its lowest concentration in diestrus. Immunoprecipitations reveal that progesterone prevented the estradiol-stimulated increase in radiolabeled C3 both in the media and tissue. The mechanism for the progesterone inhibition of estrogen-stimulated C3 appeared to be at the level of transcription or possibly mRNA stability since progesterone blocked the estradiol-stimulated increase in C3 mRNA.

An analysis of the role of tumor necrosis factor in the phenotypic expression of actively induced experimental allergic orchitis and experimental allergic encephalomyelitis.

The role of tumor necrosis factor (TNF) was examined in the pathogenesis of actively induced experimental allergic orchitis (EAO) and experimental allergic encephalomyelitis (EAE) in the mouse. The ability of TNF to function as either an adjuvant or to replace pertussigen in eliciting active EAO was examined by treating groups of mice immunized for disease induction with 10 micrograms of recombinant murine TNF at various time points throughout both the induction and effector phases of the disease process. All groups of animals receiving TNF ranging from 2 days before antigen challenge to 26 days postimmunization failed to exhibit significant disease in comparison to animals treated with pertussigen, indicating that TNF can neither serve as an adjuvant nor replace pertussigen in eliciting active disease. Similarly, the role of TNF in the pathogenesis of EAO and EAE was investigated by examining the ability of a known neutralizing rabbit anti-TNF IgG antibody preparation to either inhibit the development or decrease the severity of the clinical symptoms and/or the inflammatory lesions associated with the disease processes. Groups of either B6AF1 hybrid or SJL/J mice were immunized for the induction of active EAO and EAE, respectively. They were passively immunized with either 2 mg of purified anti-TNF IgG or control anti-CFA IgG at time points ranging from 2 days before to 28 days after antigen challenge. All groups, regardless of the day of treatment with anti-TNF IgG, did not exhibit a markedly significant difference in disease outcome in comparison to either groups receiving no antibody or passively immunized with anti-CFA IgG. Taken together, these results suggest that TNF does not appear to be the principal cytokine/lymphokine involved in the pathogenesis of actively induced EAO and EAE.

Diagnosis of interstitial cystitis.

We reviewed clinical and histological findings in 55 patients with interstitial cystitis and 21 with voiding dysfunction secondary to other pathological conditions. Of our interstitial cystitis patients 36% would fail to meet the research definition proposed at a recent National Institutes of Health workshop. Detrusor mastocytosis was present in 64% of our interstitial cystitis patients compared to 80% of the noninterstitial cystitis group. There was no statistically significant difference in mean detrusor mast cell counts between interstitial cystitis and noninterstitial cystitis patients. Biopsies of 12 patients who did meet the proposed National Institutes of Health research definition were evaluated by immunohistochemical techniques. Early results are inconclusive. These studies indicate that interstitial cystitis is a complex disease whose diagnosis presently still must be made from a symptom complex rather than from objective histological criteria, including mastocytosis or the presence of any specific immunoreactive cell.

Experimental allergic orchitis in mice. V. Resistance to actively induced disease in BALB/cJ substrain mice is mediated by CD4+ T cells.

Previous studies have shown that differential susceptibility to actively induced experimental allergic orchitis (EAO) exists among various BALB/c substrains. Of 13 substrains studied, BALB/cJ mice consistently exhibit greater resistance to disease induction. Such resistance is associated with a single recessive genotypic difference in an immunoregulatory locus which is unlinked to any of the known alleles distinguishing the BALB/cJ substrain. In this study, gene complementation protocols were used to study the genetics of susceptibility and resistance to EAO. The results indicate that resistance in BALB/cJ mice is not due to a mutation in the H-2Dd linked gene which governs the phenotypic expression of autoimmune orchitis. The mechanistic basis for disease resistance was examined using reciprocal bone marrow radiation chimeras generated between the disease-susceptible BALB/cByJ (ByJ) substrain and BALB/cJ (Jax) mice. All constructs, including Jax----Jax and Jax----ByJ, developed severe EAO following inoculation with mouse testicular homogenate (MTH) and adjuvants whereas control chimeras immunized with adjuvants alone did not. These results suggest that an active immunoregulatory mechanism rather than a passive one, such as the lack of T cells and/or B cells with receptors for the aspermatogenic autoantigens relevant in the induction of EAO, is responsible for disease resistance in BALB/cJ mice. The role of immunoregulatory cells was examined by pretreating BALB/cJ mice with either cyclophosphamide (20 mg/kg) or low-dose whole body or total lymphoid irradiation (350 rads) 2 days prior to inoculation. BALB/cJ mice immunized with MTH plus adjuvants generate immunoregulatory spleen cells (SpCs) that, when transferred to naive BALB/cByJ recipients, significantly reduce the severity of autoimmune orchitis observed during actively induced EAO. Treatment of such cells with either cytotoxic monoclonal anti-Thy-1.2 or anti-CD4 plus C' before transfer abrogates the ability of BALB/cJ spleen cells to inhibit disease. In contrast, neither SpCs from adjuvant-immunized BALB/cJ nor MTH plus adjuvant-primed BALB/cByJ donors significantly influenced the severity of disease observed in recipients. Taken together, these results suggest that genetically controlled resistance to EAO in BALB/cJ mice is associated with a mutation in an immunoregulatory locus whose effects appear to be mediated through a cyclophosphamide and low-dose radiation-sensitive CD4+ T-cell population.