Detection of novel leukocyte differentiation antigens on basophils and mast cells by HLDA8 antibodies.

Background: Basophils (BA) and mast cells (MC) are important effector cells in allergic reactions. Development, growth and effector cell functions are regulated by a network of cytokines, other ligands, and respective cell surface antigens.

Methods: We examined the expression of novel CD antigens on human BA, lung MC, the BA cell line KU-812, and the MC line HMC-1. Expression of surface antigens was analyzed by monoclonal antibodies (mAb) of the HLDA8 workshop and flow cytometry.

Results: Basophils were found to stain positive for CXCR1 (CD181), CCR1 (CD191), CCR2 (CD192), CCR7 (CD197), IL-18Ralpha (CDw218a), IL-18Rbeta (CDw218b), TRAIL-R1 (CD261), TRAIL-R2 (CD262), TACI (CD267), TLR-4 (CD284), LAIR1 (CD305), EMR-2 (CD312), JAM1 (CD321), and JAM2 (CD322). Lung MC were found to react with mAb against EMR-2 (CD312) and JAM1 (CD321). KU-812 cells were found to stain positive for CXCR1 (CD181), TRAIL-R2 (CD262), B7H2 (CD275), TLR-4 (CD284), JAM1 (CD321), and E-Cadherin (CD324). HMC-1 cells were recognized by mAb against TRAIL-R2 (CD262), B7H2 (CD275), LAIR1 (CD305), EMR-2 (CD312), JAM1 (CD321), and Siglec-6 (CDw327).

Conclusions: Extensive phenotyping with antibodies against novel CD antigens provides further evidence that BA and MC represent two separate hematopoietic cell lineages with unique phenotypic properties observed in mature cells as well as malignant immature cells. Further studies are required to define the functional role of these CD antigens expressed in BA and MC.