B-LCL-HROC60 Cells

B-LCL-HROC60 is an Epstein-Barr virus (EBV)-immortalized human B lymphoblastoid cell line established from tumor-infiltrating B cells (TiBc) isolated from a primary colorectal carcinoma designated HROC60. The parental tumor originated from an adult male patient with right-sided colorectal carcinoma of the CpG island methylator phenotype-high (CIMP-H) molecular subtype. Fresh tumor tissue was mechanically dissociated to obtain single-cell suspensions, and B cells were selectively immortalized in vitro using EBV-containing supernatant derived from the B95/8 marmoset cell line in the presence of cyclosporin A to suppress T- and NK-cell outgrowth. Long-term expansion resulted in a monoclonal B-cell culture, as confirmed by immunoglobulin heavy- and light-chain gene rearrangement analysis using standardized clonality assays.

B-LCL-HROC60 secretes immunoglobulin M (IgM) as its dominant isotype, with stable production over extended culture. Across the broader series of tumor-infiltrating B-cell lines generated from colorectal carcinoma, immunoglobulin secretion was restricted to a single principal isotype per clone, and no spontaneous outgrowth occurred in the absence of exogenous EBV, excluding latent in vivo EBV-driven transformation. As a monoclonal, antigen-experienced TiBc-derived line from a CIMP-H colorectal carcinoma, B-LCL-HROC60 provides a relevant in vitro model for investigating humoral immune responses within the colorectal tumor microenvironment and for characterizing functional properties of tumor-infiltrating B-cell-derived antibodies.