Cognate interaction between T helper cells and B cells. VII. Role of contact and lymphokines in the expression of germ-line and mature gamma 1 transcripts.
Complete reconstitution of Th cell function for B cell growth and differentiation was provided by plasma membranes (PM) derived from activated Th (PMAct) in combination with IL-4 and IL-5 (IL-4/IL-5). IL-5 has been shown to be essential for the secretion of all Ig isotypes by resting, conventional B cells activated by PMAct and IL-4. It was shown that in the presence of PMAct/IL-4/IL-5, a high frequency of resting B cells differentiated to express IgG1. IL-4 alone transiently induced the expression of germ-line gamma 1 transcripts. PMAct alone were ineffective at inducing germ-line gamma 1 transcript expression by resting B cells suggesting that Th-B cell contact was an insufficient signal to cause a detectable increase in the steady-state levels of gamma 1 germ-line transcripts. PMAct alone or PMAct/IL-4 did not induce the appearance of transcripts for secreted mu or mature gamma 1. IL-5, in combination with PMAct/IL-4, provided the necessary signal(s) required for the expression of secreted mu and mature gamma 1 transcripts. Therefore, IL-5 appeared to be an important if not essential differentiation factor for conventional B cells that have been activated by cognate help. It appeared that IL-5 promoted the secretion of Ig by inducing the synthesis of mature Ig transcripts.
Noelle
R J
RJ
Department of Microbiology, Dartmouth Medical School, Lebanon, NH 03756.
Shepherd
D M
DM
Fell
H P
HP
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D001483:Base Sequence; D002462:Cell Membrane / Q000502:physiology; D015870:Gene Expression; D015334:Gene Rearrangement, gamma-Chain T-Cell Antigen Receptor; D007074:Immunoglobulin G / Q000096:biosynthesis* / Q000235:genetics; D007148:Immunoglobulin mu-Chains / Q000235:genetics; D015847:Interleukin-4 / Q000494:pharmacology; D015848:Interleukin-5 / Q000494:pharmacology; D008213:Lymphocyte Activation; D008211:Lymphocyte Cooperation; D051379:Mice; D008811:Mice, Inbred DBA; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D012333:RNA, Messenger / Q000235:genetics; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology* / Q000648:ultrastructure; D013997:Time Factors
D007074:Immunoglobulin G; D007148:Immunoglobulin mu-Chains; D015848:Interleukin-5; D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; D015847:Interleukin-4