CD36 Is Differentially Expressed on B Cell Subsets during Development and in Responses to Antigen

Abstract

Of a number of mAbs made by immunization with sort-purified marginal zone (MZ) B cells, one was shown to recognize the mouse scavenger receptor CD36. Although CD36 is expressed by most resting MZ B cells and not by follicular and B1 B cells, it is rapidly induced on follicular B cells in vitro following TLR and CD40 stimulation. In response to T-independent and T-dependent Ag challenge, we found that CD36 was expressed on IgM+ plasma cells, but down-regulated on isotype-switched plasma cells in vivo. Although development, localization, and phenotype of MZ B cells in CD36−/− mice appeared normal, there was a minor block in the transitional stages of mature B cell development. In both primary and secondary Ab responses to heat-killed Streptococcus pneumoniae (R36A strain), both phosphoryl choline (PC)-specific IgM and IgG levels in CD36−/− mice were slightly reduced compared with wild-type mice. In addition, mice deficient in both TLR2 and CD36 produced significantly reduced levels of anti-PC IgG titers than those of single gene-deficient mice, suggesting that they may cooperate in an anti-PC Ab response. Collectively, these results show that CD36 does not affect the development of B cells, but modulates both primary and secondary anti-PC Ab responses during S. pneumoniae infection similarly to TLR2.

CD36-Mediated Uptake of Surfactant Lipids by Human Macrophages Promotes Intracellular Growth of Mycobacterium tuberculosis

“…TNFα can be induced through TLR2 (32, 34, 35), M.tb has TLR2 ligands (71) and CD36 has been shown to contribute to host responses in conjunction with TLR2 (32, 34, 35). We therefore investigated whether the absence of CD36 affects the TLR2-dependent release of TNFα.…”

“…CD36 imports fatty acids into a variety of tissues, such as cardiac and skeletal muscle (30), and is the major receptor for the uptake of oxidized low density lipoprotein (oxLDL), thereby contributing to the development of foamy macrophages (FMs) during atherosclerosis (31). CD36 also interacts with various TLRs to mediate their location and cellular signaling responses during both infection and sterile inflammation (32–35). …”

DNA Microarray Gene Expression Profile of Marginal Zone versus Follicular B Cells and Idiotype Positive Marginal Zone B Cells before and after Immunization with Streptococcus pneumoniae

“…Additionally, we identified Fc receptor homologue 3 (FcRH3) as a potentially immunoregulatory molecule expressed by MZ and B1 cells, but not by FO B cells (10). Recently, the scavenger receptor CD36 was identified as a marker predominantly expressed by MZ B cells (11). Taken together, it is clear that MZ B cells fill a specific niche in the splenic environment through unique expression and regulation of specific genes.…”

Differential Regulation of Protein- and Polysaccharide-Specific Ig Isotype Production In Vivo in Response to Intact Streptococcus pneumoniae

“…Thus, the location of MZB in the marginal zone of the spleen, where blood-borne bacteria first enter, allow for immediate contact of B cell and pathogen [40,41]. MZB also have a relatively high expression of CD21 for enhanced capture of, and activation by, complement-coated antigen, and of CD36 that facilitates TLR2 recognition of certain pathogen-derived adjuvanting ligands (49,50]. Finally, MZB are somewhat larger in size than FB and respond more vigorously and rapidly to various stimuli [51][52][53][54] suggesting that they are constitutively in a state of partial activation.…”