IL-5 induces a Pgp-1 (CD44) bright B cell subpopulation that is highly enriched in proliferative and Ig secretory activity and binds to hyaluronate.
Pgp-1 expression was examined in unstimulated B cell populations and in B cells activated with several polyclonal stimuli. Flow cytometry analysis demonstrated that Pgp-1 expression increased when B cells were activated with supernatant of cloned Th2 cells, with LPS, or with IL-5, stimuli that induced polyclonal proliferation and differentiation. IL-5-primed B cells were phenotypically unique and could be divided into two distinct subpopulations based on the brightness of Pgp-1 expression. Furthermore, sterile sorting experiments showed that proliferating and differentiating B cells were highly enriched in a Pgp-1-bright, Ia-dull, B220-dull subpopulation. The possibility that Pgp-1 expressed on activated B cells functions as an adhesion molecule was evaluated by assessing adhesion of activated B cells to defined substrates. It was found that IL-5-activated B cells bound strongly to hyaluronate-coated surface, and this binding was specifically inhibited by anti-Pgp-1 Ab. These findings suggest that Pgp-1 expression is a useful marker which, under defined conditions, identifies the proliferating and differentiating subset of activated B cells. Moreover, the Pgp-1 bright subset of IL-5-primed B cells binds to hyaluronate in a Pgp-1-dependent manner that suggests a potential role of Pgp-1 in the in vivo adherence and trafficking of activated B cells.
Murakami
S
S
Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.
Miyake
K
K
June
C H
CH
Kincade
P W
PW
Hodes
R J
RJ
D000818:Animals; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D006820:Hyaluronic Acid / Q000378:metabolism*; D007136:Immunoglobulins / Q000378:metabolism*; D015847:Interleukin-4 / Q000494:pharmacology; D015848:Interleukin-5 / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008213:Lymphocyte Activation; D051379:Mice; D010641:Phenotype; D016201:Receptors, Lymphocyte Homing / Q000096:biosynthesis* / Q000502:physiology; D011994:Recombinant Proteins / Q000494:pharmacology
D007136:Immunoglobulins; D015848:Interleukin-5; D008070:Lipopolysaccharides; D016201:Receptors, Lymphocyte Homing; D011994:Recombinant Proteins; D015847:Interleukin-4; D006820:Hyaluronic Acid