B-LCL-HROC57 Cells

B-LCL-HROC57 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 HROC57. The parental tumor originated from an adult male patient with right-sided colorectal carcinoma exhibiting neuroendocrine differentiation and advanced-stage disease. 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 inhibit T- and NK-cell outgrowth. Long-term expansion yielded a stable monoclonal B-cell culture, as confirmed by immunoglobulin gene rearrangement analysis.

B-LCL-HROC57 secretes immunoglobulin G (IgG) as its exclusive isotype, with stable production over prolonged culture. In cell-based binding assays, IgG derived from B-LCL-HROC57 demonstrates measurable binding to allogeneic colorectal carcinoma cell lines, with intermediate binding intensity relative to other TiBc-derived IgGs. Immunofluorescence analyses indicate predominantly intracellular target recognition in tumor cells. No spontaneous B-cell outgrowth occurs in the absence of exogenous EBV during culture establishment, excluding latent EBV-driven transformation in vivo. As a monoclonal, antigen-experienced tumor-infiltrating B-cell line, B-LCL-HROC57 represents a defined model for investigating humoral immune responses in colorectal carcinoma and for identifying tumor-associated antigens recognized by locally expanded B-cell clones.