Head-to-head comparison of protocol modifications for the generation of collagen-induced arthritis in a specific-pathogen free facility using DBA/1 mice.

Collagen-induced arthritis (CIA) is a widely used mouse model for studying inflammatory arthritis (IA). However, CIA induction protocols differ between laboratories, and direct comparison between protocol variations has not been reported. To address this issue, DBA/1 mice housed in conventional and specific-pathogen free (SPF) facilities were administered various combinations of two doses of collagen type II (CII) in complete (CFA) or incomplete Freund's adjuvant (IFA); some mice were also injected with lipopolysaccharide (LPS) and/or additional CII at specific intervals. Mice were evaluated for IA over the subsequent 2 months. Depending directly on the combination of CII, CFA, IFA, and LPS used, the incidence of IA ranged between 20%-100%, and severity extended from mild to severe even in an SPF environment. Our results demonstrate for the first time in head-to-head comparisons that specific variations in the use of CII, CFA, IFA, and LPS can induce a range of arthritic disease intensity and severity in an SPF facility. Thus, distinct experimental settings can be designed for robust assessment of factors that either exacerbate or inhibit arthritis pathogenesis. Furthermore, by achieving 100% incidence in an SPF facility, the protocols provide a practical and humane benefit by reducing the number of mice necessary for experimental assessment.

To drive or be driven: the path of a mouse model of recurrent pregnancy loss.

This review is an example of the use of an animal model to try to understand the immune biology of pregnancy. A well-known model of recurrent spontaneous pregnancy loss is put in clinical, historical, and theoretical context, with emphasis on T cell biology.

Indirect ELISA and indirect immunofluorescent antibody assay for detecting the antibody against murine norovirus S7 in mice.

To evaluate murine norovirus (MNV) infection in laboratory mice, we attempted to develop an enzyme-linked immunosorbent assay (ELISA) system and an indirect immunofluorescent antibody (IFA) assay for detecting the anti-MNV-S7 antibody in mice. MNV-S7, which was isolated in Japan, was used in both assays. The antigen for ELISA was prepared by ultracentrifugation of culture supernatants of RAW 264 cells infected with MNV-S7. Positive sera were obtained from 6-week-old, female C57BL/6JJcl mice inoculated orally with MNV-S7. IFA against infected RAW 264 cells was able to discriminate positive sera from negative sera. Indirect ELISA was performed using 96-well ELISA plates coated with formalin-treated MNV-S7 antigen. In this ELISA system, mouse sera obtained 2 weeks after infection or later showed significantly high OD values and were judged positive. An equal level of anti-MNV-S7 antibody response was observed in BALB/cAJcl, C57BL/6JJcl, DBA/2JJcl, and Jcl:ICR mice; whereas, C3H/HeJJcl mice demonstrated slightly lower antibody production 4 weeks after infection. We also used this ELISA system to evaluate 77 murine serum samples obtained from 15 conventional mouse rooms in research facilities in Japan and found that approximately half of the serum samples contained antibody to MNV-S7. We found that some serum samples were negative for antibodies to mouse hepatitis virus and Mycoplasma pulmonis but positive for antibody to MNV-S7. The results suggest that the MNV infection is more prevalent than other infections such as mouse hepatitis virus and Mycoplasma pulmonis in conventional mouse colonies in Japan, as is the case in other areas of the world.

The persistence of paternal antigens in the maternal body is involved in regulatory T-cell expansion and fetal-maternal tolerance in murine pregnancy.

PROBLEM: Mammalian pregnancy is a state of immunological tolerance and CD4(+) CD25(+) regulatory T cells (Treg) contribute to its maintenance. Knowing that Treg act in an antigen-specific way during pregnancy, we hypothesized that they are generated after maternal immune cells encounter paternal antigens. METHOD OF STUDY: We mated wild type females with transgenic green fluorescent protein (GFP) males in an allogenic setting and killed them on different days of pregnancy. RESULTS: Presence of paternal and maternal MHC class II(+) cells in vaginal lavage on day 0.5 of pregnancy was confirmed. Thus, antigen presentation may take place early during pregnancy in the periphery either by the direct or indirect pathways. Foxp3(+) cells known to have regulatory activity could be detected on day 2 of pregnancy in lymph nodes and shortly after implantation at the fetal-maternal interface. CONCLUSION: Our data suggest that paternal antigens are processed early during pregnancy, which leads to the generation of Treg. The continuous release of placental antigens into the maternal circulation allows the maintenance of a Treg population which is specific for paternal antigens and mediates tolerance toward the semi-allogeneic fetus until the time point of birth.

Arthritis in mice that are deficient in interleukin-1 receptor antagonist is dependent on genetic background.

OBJECTIVE: To determine the effect of deletion of interleukin-1 receptor antagonist (IL-1Ra) protein in an animal model of rheumatoid arthritis. METHODS: BALB/c mice deficient in IL-1Ra (IL-1Ra(-/-)) were bred with collagen-induced arthritis (CIA)-susceptible DBA/1 mice and B10 mice transgenic for HLA-DRB1*0101 (B10.DR1). After generation of IL-1Ra(-/-) mice on the DBA/1 and B10.DR1 backgrounds, the mice were observed for the development of spontaneous arthritis and immunized for induction of CIA. RESULTS: We found that although BALB/c mice deficient in IL-1Ra (BALB/c(-/-)) spontaneously developed chronic inflammatory arthritis, DBA/1 IL-1Ra-deficient (DBA/1(-/-)) and B10.DR1 IL-1Ra-deficient (B10.DR1(-/-)) mice did not. Splenocytes from BALB/c(-/-) mice produced elevated levels of IL-2, IL-4, IL-6, IL-10, IL-17, and granulocyte-macrophage colony-stimulating factor in response to anti-CD3 stimulation. After immunization with type II collagen (CII), DBA/1(-/-) and B10.DR1(-/-) mice had a significantly earlier onset of CIA, and with increased severity compared with IL-1Ra(+/+) mice. Immunization of BALB/c(-/-) mice with CII did not aggravate spontaneous arthritis. All of the immunized mice developed antibodies to CII that correlated with arthritis severity. Levels of antibody to CII in the BALB/c(-/-) strain were relatively low. CONCLUSION: These data indicate that the spontaneous arthritis of IL-1Ra deficiency is highly dependent on non-major histocompatibility complex genes and that autoimmunity to CII is not the major disease-inducing event. Class II immune response genes are more important for the regulation of CIA, and although these 2 models of arthritis share many pathogenic mechanisms, they also have significant differences.

Immune reactions in different mouse strains.

The responses of immunocompetent cells to thymus-dependent antigen differ in mice of different strains. Immunization stimulated phagocytic activity of peritoneal macrophages in CBA/CaLac, DBA/2, and BALB/c mice and suppressed it in CC57W mice. By the formation of antibody-producing cells in the spleen in response to thymus-dependent antigen DBA/2 and CBA/CaLac mice can be classified as high responders, BALB/c mice as medium-responders, and C57Bl/6 and CC57W mice as low responders.

Increased serum IgG1 levels and reduced numbers of B-1 B cells in DBA/2J mice.

B-cell heterogeneity studies have historically focused upon BALB/c mice and their derivatives. In contrast, the B cells of DBA/2J mice, a prototype strain for the study of the endogenous minor lymphocyte stimulatory (Mls) viral superantigen Mls-1a, have not been extensively investigated. DBA/2J B cells, by functioning as Mls-1a antigen-presenting cells, influence their own differentiation and diversity by inducing the proliferation and differentiation of specific CD4 T-cell subsets. In this report, the B cells of DBA/2J and BALB/c mice were compared for their ability to restore B-cell function in severe combined immunodeficient (SCID) recipients. Although spleen and bone marrow cells from these strains exhibited similar restoration of serum IgM production, the transfer of DBA/2J B cells into SCID mice led to greater IgG1 production. The peritoneal cells of DBA/2J mice consisted of a lower percentage of B-1 B cells and were less capable of restoring B-cell function after transfer into SCID recipients. These differences are discussed with respect to the possible role of viral superantigens in influencing B-lymphocyte diversity.

The effect of blood transfusion on susceptibility to bacterial infection in genetically defined mouse models.

BACKGROUND: Blood transfusions suppress immune function and increase susceptibility to infection, but the effects are not consistent. STUDY DESIGN AND METHODS: Genetically defined mouse strains with the same or different haplotypes were used as blood transfusion recipients and donors. Transfused animals were subjected to cecal ligation and puncture (CLP) and followed for survival or were injected intravenously with Candida albicans to follow clearance of the Candida from the kidneys. RESULTS: BALB/c (H-2d) mice transfused with C3H/HeJ (H-2k) or DBA/2 (H-2d) blood followed by CLP showed significantly lower survival (7 and 10%) than mice transfused with syngeneic blood (61%) or saline controls (56%). Lower survival was also observed in C3H/HeJ (H-2k) mice transfused with BALB/c (H-2d) blood and subjected to CLP (25%) compared with syngeneic transfusion (80%) or saline controls (70%). C57BL/6J (H-2b) mice showed minimal increases in mortality after CLP after transfusion with blood from C3H/HeJ (H-2k) (60% survival), DBA/2 (H-2d) (70% survival), or BALB/c (H-2d) mice (90% survival). When C. albicans was infused intravenously into transfused mice, a similar pattern of altered resistance to infection was found. CONCLUSION: The ability of blood transfusions to increase susceptibility to bacterial infection appears to be dependent on genetic factors unrelated to the major haplotype.

Pharmacokinetic study of anti-interleukin-6 (IL-6) therapy with monoclonal antibodies: enhancement of IL-6 clearance by cocktails of anti-IL-6 antibodies.

The use of inhibiting cytokine-binding-proteins (CBPs) such as soluble cytokine receptors and anticytokine antibodies is considered for the treatment of cytokine-dependent diseases. The pleiotropic cytokine interleukin-6 (IL-6) is a target for immunointervention in numerous pathologic situations, including multiple myeloma, B-cell lymphoma, and rheumatoid arthritis. An antitumor response was obtained in the treatment of a patient with multiple myeloma. A controversial issue is to evaluate whether the carrier effect of the CBPs might limit their efficiency in blocking the target cytokine. We analyzed the pharmacokinetics of radiolabeled IL-6 in mice treated with various combinations of anti-IL-6 antibodies. We show that injection of one or two antibodies led to the stabilization of the cytokine. Conversely, simultaneous treatment with three anti-IL-6 antibodies, binding to three distinct epitopes, induced the rapid uptake of the trimeric immune complexes by the liver and the elimination of IL-6 from the central compartment. The use of cocktails of three antibodies binding simultaneously to a cytokine thus provides a new means of enhancing the clearance of the target molecule and should help in the design of antibody-based clinical trials by overcoming the problem of the accumulation of the cytokine in the form of monomeric immune complexes.

Agalactosyl glycoforms of IgG autoantibodies are pathogenic.

The glycosylation of IgG results in many different glycoforms. A large body of correlative data (including remission of arthritis during pregnancy) has suggested that IgG molecules lacking galactose were associated with rheumatoid arthritis. We now demonstrate that agalactosyl IgG glycoforms are directly associated with pathogenicity in murine collagen-induced arthritis. We show that passive transfer of an acute synovitis in T-cell-primed mice can be enhanced by using IgG containing autoantibodies to type II collagen when the antibodies are present as the agalactosyl glycoform. Thus, nonpathogenic doses of autoantibodies can be made pathogenic by altering their glycosylation state.

Differential pattern of infection and immune response during experimental oral candidiasis in BALB/c and DBA/2 (H-2d) mice.

We used an experimental model of oral candidiasis in the mouse to investigate the impact of the introduction of Candida albicans into a Candida-free system. We report that 2 strains of mice with the same major histocompatibility complex haplotype (H-2d) display different kinetics of primary oral infection after topical application of the same inoculum. The mucosal reactions in both DBA/2 and BALB/c mice involve a similar recruitment of CD4+ and CD8+ T cells and of MAC-1+ cells in mucosal tissue during the infection. A carrier state is maintained following the resolution of the infection in both strains and is associated with the persistence of intraepithelial CD4+ T cells. However, there is a time-specific recruitment of gamma delta T cells that coincides with a dramatic decrease in viable Candida in the mucosal tissue; this occurs on day 3 in BALB/c mice and on day 6 in DBA/2 mice. The denouement of an oral contact with Candida is also different in the 2 mouse strains, cell-mediated immunity being triggered in DBA/2 mice but not in BALB/c mice. The different kinetics of Candida clearance in BALB/c vs DBA/2 mice may therefore signal a differential priming of T cell subsets whose modalities do not appear to be associated with the H-2 complex.

Responsiveness of susceptible inbred mice to Yersinia pseudotuberculosis serovar III infection.

The susceptibility of BALB/c, C57BL and BDF1-hybrid mouse strains to Yersinia pseudotuberculosis serovar III infection was studied. The bacterial load in the viscera and brain and the host responses at different levels, i.e. blood, peritoneal cavity and organs were determined. Blood cell parameters and peritoneal exudate cell population were evaluated during the infection using the automated hematologic analyzer Technicon H-1. It was found that BDF1-hybrid mice produced an early peritoneal inflammatory response, while in BALB/c and C57BL mice it was not observed. The high susceptibility of C57BL was associated with a great number of microorganisms in the organs and with the corresponding histological changes. It was shown that the magnitude of the inflammation induced by Y. pseudotuberculosis varied among the host strains used. The variations of the susceptibility to Y. pseudotuberculosis among inbred mouse strains suggest the possible role of genetic factors regulating the host defence.

Murine susceptibility to mercury. II. autoantibody profiles and renal immune deposits in hybrid, backcross, and H-2d congenic mice.

Inorganic mercury causes systemic autoimmunity and/or immune-complex deposits in strains of mice carrying certain H-2 haplotypes, for example H-2s and H-2d. This study aimed at describing the genetic mechanisms regulating these reactions. Inbred SJL, C57BL/6J (B6), C57BL/10J (B10), and DBA mice, F1(SJL x DBA), F1(SJL x B6), and F2(SJL x B6) hybrids, and mice derived from a backcross of SJL or B6 mice to F1(SJL x B6) hybrids were given subcutaneous injections of either 1.6 mg HgCl2/kg body wt or 0.1 ml NaCl every third day for 6 weeks. SJL mice developed a high titer of serum antinucleolar antibodies (ANoA) of the IgG class targeting the nucleolar protein fibrillarin and a significantly increased titer of IgG and C3 colocalized as granular deposits in the renal mesangium and vessel walls. The B6 and DBA strains lacked ANoA and showed no increase in titers of immune deposits. Nine percent of mercury-treated F1(SJL x DBA) hybrids developed IgG-ANoA which were of a low titer, and only occasional hybrids showed an increased titer of granular mesangial IgG deposits. Mercury treatment induced ANoA of low titer in 41% of F1(SJL x B6) hybrids, and 24% had increased granular mesangial immune deposits. Four of 61 mercury-treated BC-[SJL x F1(SJL x B6)] mice showed ANoA which were of a high titer and targeted the nucleolar protein fibrillarin. ANoA were not found in 55 mercury-treated F2(SJL x B6) hybrids or in 56 mercury-treated mice derived from a backcross of B6 mice to F1(SJL x B6) hybrids. Increased mesangial immune deposits were regularly accompanied by vessel wall deposits in F1- and F2(SJL x B6) hybrids, but only 53% of BC(SJL x F1[SJL x B6]) mice with increased mesangial deposits had vessel wall deposits. Vessel wall immune deposits were only present in mice with increased mesangial deposits. A majority of mice which developed significantly increased titers of mesangial IC deposits showed no ANoA. In conclusion, the susceptibility in SJL mice to develop ANoA during mercury treatment, which has been shown to reside in the H-2A locus, was codominantly inherited in a cross with mice carrying the H-2b and H2d haplotypes. Non-H-2 genes dampened ANoA expression to a degree which varied between the strains. Since renal vessel and mesangial IC deposits developed in backcross mice lacking serum ANoA, these deposits must contain IC not related to fibrillarin-antifibrillarin.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of various anti-T cell receptor antibodies on the development of type II collagen-induced arthritis in mice.

Recent genetic studies of David and coworkers suggest that subsets of T cells utilizing specific V beta TcR genes may play important roles in the susceptibility to collagen-induced arthritis (CIA). Hence, in vivo depletion of such T cell subsets may significantly affect the development of CIA. To address this possibility, we first examined the effects of in vivo treatments with various monoclonal antibodies (mAbs) that are specific for particular TcR V beta families on the induction of CIA. Results presented in this study demonstrated that treatments with either anti-V beta 6, anti-V beta 8 or anti-V beta 11 did not suppress the development of arthritis in collagen-immunized mice. While combined treatments with these V beta specific mAbs which resulted in the in vivo elimination of V beta 6+, V beta 8+ and V beta 11+ T cells were not very effective in preventing the onset of CIA, the severity of the arthritic disease was somewhat reduced in animals that had received the triad of anti-V beta mAbs. By contrast, depletion of T cells expressing the alpha beta receptors by in vivo treatments with a pan anti-alpha beta mAb significantly decreased the incidence of CIA. Therefore, although an effect on the development of CIA was achieved by in vivo treatments with a mAb that detects all alpha beta + T cells, the elimination of only a few subsets of T cells which included the V beta 6+, V beta 8+, and V beta 11+ cells did not profoundly alter the incidence of CIA.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Mlsa-like effect of CBA/J anti DBA2 antibody in in vitro MLRs between Mls incompatible combinations.

Antisera from CBA/J (H-2k,Mlsa) mice hyperimmunised with DBA2 (H-2d,Mlsa) and/or AKR (H-2k,Mlsa) splenocytes, can block in vitro MLRs against Mlsa determinants. These two antisera are furthermore specifically cytotoxic against targets expressing H-2 components but not against Mlsa-bearing targets. In these experimental models the anti-Mlsa-like effects of CBA/J anti-DBA2 and CBA/J anti AKR antibodies seem to be associated with an autoreactive immune response in CBA/J mice elicited by DBA2 and AKR splenocytes, respectively. In this report we propose that anti-Mlsa antibodies can also be generated in a situation in which Mlsa is presented as 'altered self' in conjunction with allo-determinants.

Distinct patterns of protective antibodies are generated against Borrelia burgdorferi in mice experimentally inoculated with high and low doses of antigen.

We have studied the development of clinical arthritis and the generation of protective antibodies in two normal, inbred strains of mice either infected by ticks or experimentally (subcutaneous) inoculated with increasing numbers of Borrelia burgdorferi organisms. AKR/N mice developed only mild and DBA/2 mice only marginal clinical arthritis irrespective of the route of infection or the numbers of spirochetes (10-10(8)) inoculated. In contrast, immunodeficient SCID mice developed severe chronic arthritis under similar conditions, but with a delayed onset at lower numbers of needle-inoculated spirochetes or after tick bite. AKR/N and DBA/2 mice inoculated with either 10(4) (and fewer) B. burgdorferi organisms or via experimentally infected ticks generated antibodies with specificities for a variety of B. burgdorferi antigens except those to the outer surface proteins A and B (OspA, OspB). In contrast, mice inoculated with more than 10(4) spirochetes (10(5)-10(8)) developed in addition antibodies to OspA and OspB. Most notably, all three types of immune sera taken from DBA/2 mice showed similar capacities to confer protection on SCID mice against subsequent challenge with viable B. burgdorferi organisms. The data not only demonstrate that the quality of humoral immune responses to B. burgdorferi in mice is determined by the antigenic load, they also indicate the existence of further protective antibodies with specificities distinct from OspA and OspB.

Susceptibility to pristane-induced arthritis is altered with changes in bowel flora.

Pristane-induced arthritis (PIA) is unique among the animal arthritides in that a non-infectious, non-antigenic oil induces a chronic immune based arthritis with a prolonged delay between exposure to the inciting agent and development of the disease. Mice with pristane-induced arthritis have elevated T cell and humoral responses to the 65 kDa heat shock protein derived from Mycobacterium bovis (hsp65) and in common with several other models of autoimmune diseases the incidence of PIA is markedly suppressed by preimmunisation with hsp65 in Freund's incomplete adjuvant (Thompson et al. (1990) Eur. J. Immunol. 20, 2479). Recent studies have investigated how autoimmune reactions to heat shock proteins are involved in the development of arthritis. Arthritic CBA/Igb mice given pristane alone develop antibodies to both hsp65 and GroEl (bacterial 60 kDa heat shock proteins) and to hsp58 (the mammalian equivalent). Moreover, the splenic T cells of such mice proliferate vigorously in response to both bacterial and mammalian 60 kDa heat shock proteins. Remarkably, the anti-hsp65 antibody response in normal mice rises rapidly with age, directly correlating with the age related incidence of PIA. In addition, specific pathogen free mice (SPF) maintained in an isolator have negligible anti-hsp65 responses but these convert to positive responses if the animals are exposed to the open part of the animal facility (Thompson et al. (1992) Arthritis Rheum. 35, 139).(ABSTRACT TRUNCATED AT 250 WORDS)

Stimulation of natural killer cell numbers but not function in leukemic infant mice: a system primed in infancy allows survival in adulthood.

Infant mice (< 3-4 weeks) demonstrate no detectable natural killer (NK)-cell-mediated immunity. The aim of the present work was to assess, quantitatively and functionally, the possibility that prostaglandin E2, (PGE2), an NK cell inhibitor, may be responsible for the absence of NK-cell-mediated activity in normal and/or erythroleukemia-bearing infant DBA/2 mice prior to the normal age-related onset of NK-cell-mediated lytic capacity. Infants (7 days after birth) were exposed daily to indomethacin via intraperitoneal injection for 10 days and/or recombinant interleukin-2 (rIL-2) daily for 4 days. Significant increases in the number of NK cells in both the spleen and bone marrow were found after 10 days of indomethacin or 4 days of rIL-2 in normal mice. The spleens but not the bone marrow of infants treated with indomethacin from tumor onset (7 days after birth) contained significantly more NK cells 10 days later than did control (tumor+vehicle) infants. Infants treated with rIL-2 during the last 4 days of tumor bearing, i.e., days 13-16 after birth, contained significantly more NK cells in both their spleen and bone marrow, while combined administration of rIL-2 and indomethacin to tumor-bearing, but not normal, infants resulted in a more than additive increase in the NK cell numbers in both organs relative to control (tumor+vehicle or vehicle alone). However, in neither normal nor tumor-bearing infants, could indomethacin, rIL-2, or a combination of both, induce the development of NK-cell-mediated functional (lytic) activity in spite of the generation, in nearly all instances, of high levels of NK cells in the presence of these agents. The observations collectively suggest that the lack of functional (lytic) reactivity of infant-source NK cells, in the presence of agents which potently enhance adult-source NK cells, reflects (1) the innate immaturity of infant NK lineage cells, or (2) the presence in infant NK-cell-containing organs of a function-suppressive mechanism which is indomethacin insensitive, i.e., not PGE2-mediated. The significantly prolonged survival, and even cure, of infant leukemic mice treated with indomethacin and/or rIL-2 may result from the agent-mediated elevated levels of precursor NK cells coming under the influence of some age-related, as yet unidentified, endogenous factor imbuing them with functional capacity.

Tissue distribution of Mtv-7-like exogenous retroviral transcripts and clonal deletion of V beta 6+ T cells in Mls-1b BALB/c mice.

We have previously described an Mls-1a-like clonal deletion of mature CD4+ T cells which express V beta 6 and V beta 8.1 chains of the TCR in half of the mice of a BALB/c, Mls-1b colony (BALB/c IC). This occurs in the absence of the Mtv-7 provirus which is responsible for the clonal deletion in Mls-1a mice. We developed a polymerase chain reaction assay in order to study the presence of retroviral transcripts homologous to the viral superantigen gene (vSAG) of Mtv-7 and Mtv-6 in various tissues. Mtv-7 homologous transcripts were present in the mammary glands of lactating BALB/c IC mice and in the thymuses and/or spleens of BALB/c IC virgin mice with deletion of V beta 6+ lymph node T cells, and not in BALB/c IC with normal V beta 6 expression. These results indicate that this BALB/c colony is infected with an exogenous mouse mammary tumour virus (MMTV) whose vSAG is similar to Mtv-7, as recently reported. Thymectomies performed at 4-5 weeks of age (at least 4 weeks before detection of clonal deletion), did not affect the occurrence of clonal deletion in peripheral lymph nodes when tested 20 weeks later. This suggests that clonal deletion can be achieved without further intrathymic contact with the antigen. Since MMTV is transmitted through milk and is likely to be present in the gut, we evaluated the percentage of V beta 6+CD4+ T cells within the gut intraepithelial lymphocyte (IEL) population. Mice with normal V beta 6 expression in lymph nodes may show partial deletion of V beta 6+CD4+ IEL.(ABSTRACT TRUNCATED AT 250 WORDS)

Contribution of major histocompatibility complex (MHC) to upregulation of anti-DNA antibody in transgenic mice.

Genes linked to the MHC class II contribute to human and murine lupus, but multiple genes are required to produce and upregulate pathogenic autoantibodies. In NZB/NZW mice, nephritogenic IgG anti-dsDNA is provided by NZW (H-2z), but the origin of the upregulating signals is unknown. They could be from NZB (H-2d) or NZW (H-2z) or require heterozygocity. Our aim was to determine whether NZW can provide upregulating signals for the nephritogenic autoantibody introduced to normal mice via transgenes encoding a NZB/NZW IgG2a antibody to DNA. These transgenic mice spontaneously secrete serum IgG2a anti-DNA, some develop clinical nephritis with proteinuria and azotemia, but none die of fatal nephritis. We bred mice to produce offspring of H-2b/d, H-2b/b, H-2b/z and H-2d/z haplotypes (H-2b, H-2d and H-2z derived from C57BL/6, BALB/c and NZW, respectively). Transgenic H-2b/d mice had significantly higher levels of serum anti-DNA antibodies compared with H-2b/b haplotypes from 20 to 40 weeks of age (P < 0.05). However, unlike NZB/NZW mice, they did not show sustained upregulation of anti-DNA antibodies. The serum levels of IgG anti-DNA of transgenic mice declined after 30 weeks of age. In order to determine whether NZW can provide upregulating signals, we introduced the NZW background into transgenic H-2b/d mice in an attempt to increase both quantities of anti-DNA and prevalence of nephritis. However, serum levels of anti-DNA antibodies were similar in transgenic mice of H-2b/z and H-2d/z haplotypes. The anti-DNA levels declined with age in both groups. No mice developed fatal nephritis.(ABSTRACT TRUNCATED AT 250 WORDS)