Biomedical subjects
M J Marx
Publications and source records attributed to M J Marx.
Modified hemolytic plaque technique for the detection of bluetongue virus antibody-forming cells.
A hemolytic plaque assay was developed for the detection of antibody-forming cells to bluetongue virus (BTV). Sheep erythrocytes (SRBC), onto which BTV had been absorbed, served as the indicator of lysis due to the presence of BTV antibody-forming cells. The ratio of BTV to SRBC was found to be critical for optimum hemolytic plaque formation. For routine use, 50 mul of 12% BTV SRBC, 0.1 ml of a spleen cell suspension, and 0.5 ml of 0.5% agarose in a balanced salt solution were mixed and plated on a microscope slide precoated with 0.1% aqueous agarose. Slides were incubated for 1 h at 37 C in a humidified incubator and subsequently flooded with 0.4 ml of a 1:15 dilution of complement. Incubation was continued for a further 2 h before the hemolytic plaques were scored. It was not possible to establish BTV serotype specificity by this technique.
Kinetics of the IgM and IgG immunological response to sheep erythrocytes and bluetongue virus in mice.
The IgM and IgG response of mice to sheep erythrocytes (SRBC) and bluetongue virus (BTV) was determined by means of haemolytic plaque assays. Maximum primary IgM response to SRBC occurred after 4 days but declined rapidly to 4% of the maximum by Day 9. A lag period of about 2 days was observed in the appearance of IgG haemolytic plaque-forming cells (PFC) but they reached a maximum after 6-9 days. Secondary immunization resulted in the stimulation particularly of IgG PFC and from Day 6 onwards IgG predominated in the immunological response. The IgM response to BTV was remarkably similar to that observed when SRBC were used as antigen. IgG PFC, however, appeared within a day of the IgM, reaching a peak on Days 4-5. From then onwards, IgG PFC predominated in the response. At BTV concentrations of up to 10 mug per mouse, the virulent strain of BTV type 3 produced the weakest response. At higher antigen concentrations there was very little difference in the response to the serotypes tested, although the virulent strain of BTV type 4 tended to produce the strongest response.