Antibodies of surface antigens of lymphocytes and lymphoblastoid cells in cold-agglutinin-positive sera from patients with Mycoplasma pneumoniae infection

Abstract

IgM antibodies reacting in the cold with surface antigens of normal human blood lymphocytes were demonstrated by indirect immunofluorescence (IFL) in cold-agglutinin-positive sera from 21 patients with Mycoplasma pneumoniae (MP) infection. Twenty to fifty per cent of the lymphocytes were stained. MP sera reacted also with 75%-100% of cells from two lymphoblastoid cell lines and one Burkitt lymphoma line and with about 80% of peripheral blood lymphocytes from one patient with chronic lymphatic leukaemia. The IFL reaction was negative with cells from leukaemic lymphoid T-cell line (Molt-4). Lymphocyte fractionation experiments gave no evidence of a selective reactivity of MP sera and B or T lymphocytes of peripheral blood. Removal of cold agglutinins from the MP sera by absorption with human O erythrocytes significantly reduced the IFL reactivity with lymphocytes and lymphoblastoid cells, indicating the presence of I antigen on these cells. Furthermore, lymphoblastoid cells but not Molt lymphoid cells absorbed out most of the cold erythroagglutinins.