alpha beta T cell receptor-positive intraepithelial lymphocytes with CD4+, CD8- and CD4+, CD8+ phenotypes from orally immunized mice provide Th2-like function for B cell responses.
Our previous studies have shown that murine alpha beta TCR+ intraepithelial lymphocytes (IEL) contained T cells that can provide B cell help. In this study, we have examined the three subsets of alpha beta TCR+ IEL for Ag-specific helper function and cytokine production because alpha beta TCR+ IEL are divisible into three subsets including CD4+, CD8- T cells, CD4+, CD8+ double positive (DP) T cells, and CD4-, CD8+ T cells. When these three subsets of alpha beta TCR+ IEL from C3H/HeN mice (H-2k) orally immunized with SRBC were cultured with splenic B cells, adherent cells, and SRBC, both CD4+, CD8- and DP T cell fractions supported IgM, IgG1, and IgA anti-SRBC responses, whereas the CD4-, CD8+ T cell subset did not exhibit helper function. Addition of anti-I-Ak mAb resulted in the reduction of SRBC-specific PFC responses, whereas anti-H-2Kk mAb did not affect the CD4+, CD8- and DP T cell-supported B cell responses. Furthermore, when these CD4-bearing T cells from mice orally immunized with SRBC were co-cultured with B cells and adherent cells in the presence of unrelated Ag (e.g., horse RBC), SRBC-specific B cell responses were not induced. When type 1 and type 2 Th cell cytokine production was examined by IFN-gamma, IL-2-, IL-4-, and IL-5-specific enzyme-linked immunospot assays, increased numbers of IL-4- and IL-5-secreting type 2 Th cells, whereas lower numbers of IFN-gamma and IL-2-producing type 1 Th cells were seen in CD4+, CD8- and DP T cell fractions on in vitro stimulation with SRBC. In the case of CD4-, CD8+ T cells, approximately equal and low numbers of type 2 cytokine-producing cells were noted in both SRBC-stimulated and -unstimulated cultures. Furthermore, when different fractions of IEL T cells from Ag-stimulated and -unstimulated cultures were characterized for cytokine-specific mRNA by reverse transcription polymerase chain reaction, stronger bands for IL-4 and IL-5 were detected in both CD4+, CD8- and DP IEL subsets when compared with the unstimulated cells. In contrast, the change in intensity of the band of polymerase chain reaction product for IFN-gamma was slight or unchanged in Ag-stimulated CD4-bearing IEL when compared with unstimulated cells.(ABSTRACT TRUNCATED AT 400 WORDS)
Fujihashi
K
K
Department of Oral Biology, University of Alabama, Birmingham Medical Center 35294.
Yamamoto
M
M
McGhee
J R
JR
Kiyono
H
H
D000284:Administration, Oral; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D015704:CD4 Antigens / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D016827:CD8 Antigens / Q000378:metabolism; D016207:Cytokines / Q000096:biosynthesis; D004847:Epithelial Cells; D004848:Epithelium / Q000276:immunology; D004912:Erythrocytes / Q000276:immunology; D000949:Histocompatibility Antigens Class II; D006736:Horses; D007114:Immunization; D008211:Lymphocyte Cooperation / Q000276:immunology; D051379:Mice; D008809:Mice, Inbred C3H; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000378:metabolism*; D012756:Sheep; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology
D015704:CD4 Antigens; D016827:CD8 Antigens; D016207:Cytokines; D000949:Histocompatibility Antigens Class II; D016693:Receptors, Antigen, T-Cell, alpha-beta