Impaired antibody responses but normal proliferation of specific CD4+ T cells in mice lacking complement receptors 1 and 2.
Severely impaired Ab responses are seen in animals lacking C (complement) factors C2, C3 or C4 as well as CR1/2 (C receptors 1 and 2). The molecular mechanism behind this phenomenon is not understood. One possibility is that C-containing immune complexes are endocytosed via CR2 on B cells and presented to specific CD4+ T cells, which would then proliferate and provide efficient help to specific B cells. In vitro, B cells can endocytose immune complexes via CR1/2 and present the Ag to T cells. Whether absence of this Ag presenting function in Cr2(-/-) mice (mice lacking CR1/2) explains their low Ab response is unclear. To address this question, Cr2(-/-) and wild type mice were transferred with OVA-specific T cells, obtained from the DO11.10 strain which has a transgenic TCR recognizing an OVA peptide. The animals were subsequently immunized with sheep red blood cells (SRBC) conjugated to OVA. Interestingly, proliferation of the OVA-specific T cells was normal in Cr2(-/-) mice, although their Ab response to both SRBC and OVA was severely impaired. These observations suggest that the impaired Ab response in Cr2(-/-) mice cannot be explained by a lack of appropriate induction of T cell help.
Carlsson
F
F
Department of Genetics, Uppsala University, Uppsala, Sweden.
Getahun
A
A
Rutemark
C
C
Heyman
B
B
D019264:Adoptive Transfer; D000818:Animals; D000917:Antibody Formation / Q000235:genetics / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D008822:Mice, Transgenic; D010047:Ovalbumin / Q000276:immunology; D011951:Receptors, Complement / Q000235:genetics / Q000276:immunology*; D017464:Receptors, Complement 3d / Q000235:genetics / Q000276:immunology*
D011951:Receptors, Complement; D017464:Receptors, Complement 3d; D010047:Ovalbumin