Abstract
Group B streptococcal (GBS) infection is a major cause of neonatal mortality and morbidity. Host factors responsible for immunity to GBS include specific antibody, functional neutrophils and intact complement pathways. The role of cell-mediated immunity is unknown. To investigate the relationship between humoral immunity and cell-mediated immunity to GBS, the in vitro lymphocyte response to whole bacteria was studied in 13 healthy adult volunteers. Lymphocytes were isolated and cultured in 15% autologous serum in microtiter plates. Each well contained 2 X 106 cells and either 1) washed formalin killed type III GBS in cell to organism ratios of 1:10, 1:1, or 1:0.1, 2) PHA, or 3) SK:SD. 3H thymidine incorporation was measured at 5,6 or 7 days. The serum concentration of type III GBS antibody was determined with an enzyme immunoassay. Six of 13 adults responded to type III GBS as defined by a stimulation index of >10 or absolute count >4000 CPM. The mean serum concentration of type III GBS antibody in responders (15.5±7.4 M± SEM ug/ml) did not differ significantly from non-responders (6.0±10.1 ug/ml). Maximal response to GBS occurred at a cell/organism ratio of 1:1, (p<.05). Thymidine incorporation was significantly greater at 6 days than at 5 or 7 days (p<.005). The in vitro lymphocyte response to type III GBS may be an important determinant of host susceptibility to infection.
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Lillie, M., Cody, C., Douglas, S. et al. 1039 IN VITRO LYMPHOCYTE RESPONSE TO GROUP B STREPTOCOCCUS. Pediatr Res 15 (Suppl 4), 616 (1981). https://doi.org/10.1203/00006450-198104001-01065
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DOI: https://doi.org/10.1203/00006450-198104001-01065