Frequency of B cells expressing germ-line gamma 1 transcripts upon IL-4 induction.
Murine B cells when activated with LPS and IL-4 have been shown to secrete IgG1 and IgE with corresponding H chain gene rearrangements. Using this system it has been previously demonstrated that transcription of gamma 1 and epsilon C region genes in their germ-line configuration occurs before switch recombination. Here, for the first time, the frequencies of B cells expressing germ-line gamma 1 transcripts are analyzed using in situ hybridization methodology. The results indicate that the combination of LPS and IL-4 induces a relatively low frequency of cells (5-12%) to express germ-line gamma 1 transcripts. Germ-line gamma 1 transcript-expressing cells were first detected on day 1 of culture with LPS and IL-4 and reached a maximum by days 3 to 5. The B cells that expressed germ-line gamma 1 transcripts appeared to be activated based on size and morphology. The frequency of B cells expressing germ-line gamma 1 transcripts approximated the frequency of C gamma 1+ plasma cells that appeared later in the cultures. These data may suggest a correlation between germ-line Ig transcript expression and the frequency of B cell precursors committed to the expression of a particular isotype.
Turaga
P S
PS
Department of Microbiology, University of Texas Health Science Center, San Antonio 78284-7758.
Berton
M T
MT
Teale
J M
JM
D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology*; D015326:Gene Rearrangement, B-Lymphocyte, Heavy Chain; D005803:Genes, Immunoglobulin; D007074:Immunoglobulin G / Q000235:genetics*; D017403:In Situ Hybridization; D015847:Interleukin-4 / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D015183:Restriction Mapping; D013154:Spleen / Q000166:cytology; D014158:Transcription, Genetic
D007074:Immunoglobulin G; D008070:Lipopolysaccharides; D015847:Interleukin-4