A pivotal role of cell-bound but not soluble CD4 molecules in full development of lupus-like manifestations in MRL-Faslprcg/Faslprcgmice

Abstract

SUMMARYThe role of CD4 molecules in the autoimmune and lymphoproliferative syndrome caused by murine Fas mutations was studied using the novel systemic lupus erythematosus (SLE) model, MRL-Fas lprcg / Fas lprcg (MRL-lpr cg ) mice, in combination with the novel mutant CD4 gene producing soluble CD4 (sCD4) instead of membrane-bound CD4 (mCD4). For this purpose, various autoimmune manifestations were compared among MRL-lpr cg mice homozygous (CD4 s -lpr cg ), heterozygous (CD4 s/m -lpr cg ), and wild-type (CD4 m -lpr cg ) for the CD4 mutation. The mortality, glomerulonephritis, proteinuria, and lymphadenopathy were significantly ameliorated in CD4 s -lpr cg compared with CD4 m -lpr cg and CD4 s/mlpr cg mice, both being comparable in these clinical characteristics. In parallel with the clinical improvement, the serum levels of immunoglobulin, anti-DNA antibodies, anti-nuclear antibodies and immune complexes, and the extent of glomerular immune deposition, were significantly lower in the former. The results indicate that mCD4 is important and can not be replaced by sCD4 in full development of SLE-like manifestations, and suggest that CD4 1 T cells may aggravate the autoimmune disease by stimulating autoreactive B cells to produce autoantibodies through their helper activity in Fas mutant models. The sCD4 levels in the serum and spleen elevated with the increased accumulation of B220 1 CD4 2 CD8 2 (double-negative (DN)) T cells in CD4 s -lpr cg mice. This, together with the significantly milder lymphadenopathy associated with lower DN T cell contents in CD4 s -lpr cg than CD4 m -lpr cg mice, implies that some of abnormal DN T cells may be derived from cells of the CD4 lineage.

Treatment with testosterone or estradiol in melatonin treated females and males MRL/MpJ‐Faslpr mice induces negative effects in developing systemic lupus erythematosus

“…Serum IgM and IgG levels were determined by sandwich ELISA according to a previous report [17]. Microtiter plates were coated with 1 μg/mL goat anti‐mouse Ig heavy and light chain (H + L; Zymed Laboratories, San Francisco, CA, USA) to determine IgM or with 2 μg/mL goat anti‐mouse of Ig (H + L) for IgG at 4°C overnight, and blocked with 3% BSA in PBS.…”

“…Anti‐double‐stranded DNA (anti‐dsDNA) antibodies of IgM and IgG were also determined by sandwich ELISA [17]. Microtiter plates were coated with 50 μg/mL of poly‐l‐lysine (Sigma‐Aldrich Corp.) in PBS.…”

Sex-Dependent Effect of Melatonin on Systemic Erythematosus Lupus Developed in Mrl/Mpj-Faslpr Mice: It Ameliorates the Disease Course in Females, whereas It Exacerbates It in Males

“…Serum IgM and IgG levels were determined by sandwich ELISA according to a previous report (27). Microtiter plates were coated with 1 g/ml goat antimouse Ig heavy and light chain (H ϩ L; Zymed Laboratories, San Francisco, CA) for determination of IgM or with 2 g/ml goat antimouse Ig (H ϩ L) for determination of IgG at 4 C overnight and blocked with 3% BSA in PBS.…”

“…Anti-dsDNA antibodies of IgM and IgG were also determined by sandwich ELISA (27). Microtiter plates were coated with 50 g/ml poly-l-lysine (Sigma-Aldrich Corp.) in PBS.…”