The role of C3 and its fragments in the control of S phase entry of activated mouse B lymphocytes via the complement receptor type 2.
Complement component C3 and receptors for its activated fragments have been recognized as regulators of humoral immune responses. Cross-linked C3b and C3d will substitute for alpha B cell growth factors (alpha BCGF) produced by macrophages by stimulating activated murine B lymphocytes to enter S phase. In contrast, soluble C3d and synthetic oligopeptides--containing the amino acid sequence of the binding site of C3d to its receptor, the complement receptor type 2--inhibit the entry into S phase of alpha BCGF-stimulated B cells. There is evidence supporting the hypothesis that a portion of the C3 gene at the 3' end, encoding parts of the alpha chain, encodes an alternate C3 product with alpha BCGF activity.
Lernhardt
W
W
Cancer Research Center, La Jolla Cancer Research Foundation, Calif.
Melchers
F
F
D000595:Amino Acid Sequence; D000818:Animals; D000944:Antigens, Differentiation, B-Lymphocyte / Q000502:physiology; D001402:B-Lymphocytes / Q000502:physiology*; D002455:Cell Division / Q000276:immunology; D003176:Complement C3 / Q000502:physiology*; D006801:Humans; D015847:Interleukin-4 / Q000502:physiology; D007399:Interphase / Q000276:immunology; D008213:Lymphocyte Activation / Q000502:physiology; D051379:Mice; D010446:Peptide Fragments / Q000502:physiology; D011951:Receptors, Complement / Q000502:physiology*; D017464:Receptors, Complement 3d
D000944:Antigens, Differentiation, B-Lymphocyte; D003176:Complement C3; D010446:Peptide Fragments; D011951:Receptors, Complement; D017464:Receptors, Complement 3d; D015847:Interleukin-4