A novel gamma delta T cell receptor for antigen adds limited diversity to the gamma delta repertoire in adult thymus.
The surface expression of CD3-associated TCR chains on hybridoma cell lines derived from adult gamma delta thymocytes was analyzed. These cell lines were unusual, in that a) they expressed a surface heterodimer consisting of a 40- and a 42-kDa chain, i.e., comprised of chains different from any previously reported gamma delta-TCR all of which express C gamma 1- or C gamma 2-encoded gamma-chains; b) their CD3-associated TCR could not be categorized as alpha beta-TCR dimers, despite the similarities in m.w. of the TCR chains, because full size 1.3-kb beta-chain mRNA capable of encoding a functional beta-chain could not be detected in these cells; c) neither of the receptor chains could be precipitated with anti-C gamma 1C gamma 2-peptide antisera. Biochemical analysis demonstrated that the 42-kDa delta-chain is a novel chain, which differs from any reported delta-chains in size, charge and number of glycosylation sites. Collectively, the data on analysis of the 40-kDa chain strongly suggest that it represents a gamma-chain encoded for by the C gamma 4 locus, protein products of which have not yet been reported in the thymus. This gamma-chain was also unique, in that its isoelectric point was much lower than that of other gamma-chains. The gamma- and delta-chains on these C gamma 4-expressing hybridomas were indistinguishable from one another in size and charge (as determined by nonequivalent pH gradient electrophoresis/SDS-PAGE analysis and analysis after endoglycosidase treatment). Because the cell lines were randomly chosen from large panels of hybridomas, these results may well imply strikingly nonrandom pairing of thymocyte-derived C gamma 4 chains and the delta-chains reported here. Thus, only limited additional gamma delta repertoire diversity may be generated by availability of this gamma delta-TCR in the thymus.
Marusić-Galesić
S
S
Biological Response Modifiers Program, National Cancer Institute, Bethesda, MD 20892.
Saito
T
T
Tentori
L
L
Zuñiga-Pflucker
J
J
Raulet
D H
DH
Allison
J P
JP
Kruisbeek
A M
AM
D000375:Aging; D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology; D017252:CD3 Complex; D006825:Hybridomas / Q000032:analysis; D007106:Immune Sera; D051379:Mice; D008810:Mice, Inbred C57BL; D008970:Molecular Weight; D010455:Peptides / Q000276:immunology; D011233:Precipitin Tests; D012333:RNA, Messenger / Q000302:isolation & purification; D011948:Receptors, Antigen, T-Cell / Q000276:immunology / Q000302:isolation & purification*; D013329:Structure-Activity Relationship; D013950:Thymus Gland / Q000254:growth & development / Q000378:metabolism*
D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D007106:Immune Sera; D010455:Peptides; D012333:RNA, Messenger; D011948:Receptors, Antigen, T-Cell