Interrogation of individual intratumoral B lymphocytes from @entity2 XXXX for molecular target discovery.

@entity5 @entity1 @entity2 @entity33765
UNASSIGNED: Intratumoral B lymphocytes are an integral part of the @entity2 microenvironment. Interrogation of the antibodies they express may improve our understanding of the host response to @entity5 and could be useful in elucidating novel molecular targets. We used two strategies to explore the repertoire of intratumoral B cell antibodies. First, we cloned VH and VL genes from single intratumoral B lymphocytes isolated from one @entity2 , expressed the genes as recombinant mAbs, and used the mAbs to identify the cognate tumor antigens. The Igs derived from intratumoral B cells demonstrated class switching, with a mean VH mutation frequency of 4  %. Although there was no evidence for clonal expansion, these data are consistent with antigen-driven somatic hypermutation. Individual recombinant antibodies were polyreactive, although one clone demonstrated preferential immunoreactivity with @entity33765 ( @entity33765 ). We found that higher levels of @entity33765 antibodies were more common in @entity5 @entity1 , but measurement of @entity33765 antibody levels was not a sensitive test for detecting @entity5 . Second, in an effort to focus our recombinant antibody expression efforts on those B cells that displayed evidence of clonal expansion driven by antigen stimulation, we performed deep sequencing of the Ig genes of B cells collected from seven different @entity5 . Deep sequencing demonstrated somatic hypermutation but no dominant clones. These strategies may be useful for the study of B cell antibody expression, although identification of a dominant clone and unique therapeutic targets may require extensive investigation.
