Characterization of Monoclonal Antibodies Specific for 14-kDa Human Group V Secretory Phospholipase A2(hVPLA2)

Secretory phospholipase A2 (PLA2) consists of several 14-kDa isoforms with extensive homology, which makes it difficult to identify a specific isoform. In this study, we have developed and characterized monoclonal antibodies (MAbs) directed specifically against human group V sPLA2 (hVPLA2) derived from cultured hybridomas. These hybridomas were produced from the fusion of BALB/c-derived myeloma s/p20-Ag14 and splenocytes from mice immunized with purified recombinant hVPLA2. Three hybridomas secreting MAbs, MCL-3G1, MCL-2A5, and MCL-1B7, were selected and subcloned on the basis of their specificity to recognize hVPLA2 using solid-phase enzyme-linked immunoadsorbent assay (ELISA). The purified MAbs demonstrated a common pattern of immunoreactivity to hVPLA2, but not to human group IIa isoform (hIIaPLA2). Isotype analysis indicates that these hybridomas are of the IgG1 type. Under reducing conditions, MCL-3G1 sensitively detected hVPLA2 and demonstrated no cross-reactivity to either hIIaPLA2 or group IV cytosolic PLA2. Although specific for hVPLA2, a relatively modest signal was recognized with MCL-1B7 and MCL-2A5. These newly developed MAbs allow for determination of tissue distribution and cell-specific functions of hVPLA2.