This 1987 study describes the production and characterization of a monoclonal antibody (Tq-1) directed against phosphorylcholine (PC)-bearing antigens of the dermatophyte fungus Trichophyton quinckeanum. Researchers immunized BALB/c mice with an alum-precipitated cytoplasmic antigen fraction and fused spleen cells with myeloma cells to generate hybridomas. The resulting Tq-1 antibody was characterized as IgM and shown to bind PC hapten with high affinity. Using ELISA, immunoblotting, immunoprecipitation, and immunoelectron microscopy, the authors demonstrated that Tq-1 recognizes PC-like determinants present on multiple fungal antigens from cytoplasmic, culture filtrate, and surface fractions. PC-bearing antigens appeared early during fungal growth and persisted throughout the culture lifespan. Sera from chronically infected mice reacted strongly with the same dermatophyte antigens recognized by Tq-1, indicating these PC-containing components are immunogenic during natural infection. The findings suggest PC is a broadly distributed antigenic determinant on T. quinckeanum with potential immunological significance in dermatophyte infections.

Key findings

• Monoclonal antibody Tq-1 (IgM class) was successfully produced against T. quinckeanum and specifically recognizes phosphorylcholine-bearing antigens on the fungus
• PC-like determinants are present on multiple T. quinckeanum antigen fractions (cytoplasmic, culture filtrate, and surface) and persist from early growth stages through 20-day cultures
• Sera from chronically infected mice recognize the same PC-bearing antigens as Tq-1, demonstrating their immunogenicity during natural dermatophyte infection
• Tq-1 binding to fungal antigens is completely inhibited by pretreatment with phosphorylcholine hapten, confirming PC as the target epitope
• Immunoelectron microscopy revealed PC-bearing antigens localized primarily in the fungal cytoplasm with minimal surface membrane presence