A Monoclonal Antibody That Discriminates Strains of Citrus Tristeza Virus

Abstract

A monoclonal antibody produced to the Florida citrus tristeza virus (CTV) isolate T-36 (CTV-MCA13) reacted to decline-inducing, seedling yellows, and stem-pitting isolates of CTV from Florida, California, and Spain. It did not react to CTV isolates from these same areas, which produce symptoms primarily in Mexican lime. All CTV antigen sources used reacted strongly to anti-CTV polyclonal antibodies in double antibody sandwich enzyme-linked immunosorbent assays (ELISA) and to a previously reported broad spectrum CTV monoclonal antibody (3DF1) in comparable double antibody sandwich indirect ELISA. Discrimination of CTV isolates by CTV-MCA13 was similar in indirect ELISA with plate-trapped antigen and in double antibody sandwich indirect ELISA with antigen trapped on polyclonal antibody-coated plates. Results of immunoelectron microscopy suggest that CTV-MCA13 may react to a cryptic epitope on the viral coat protein. The monoclonal antibody is an IgG2a immunoglobin and did not react to extracts of healthy citrus or citrus infected with other viruses.