Measurement of immunoglobulin G, A and M concentrations in boar seminal plasma

How the immune system relates to the boar reproductive tract is not well defined. This is an important area of study because disease-causing agents may be transmitted through boar semen. We have previously identified porcine reproductive and respiratory syndrome virus (PRRSV) in boar semen and wanted to identify PRRSV-specific antibodies within seminal plasma. However, literature documenting total immunoglobulin concentration or the predominant immunoglobulin isotype in boar semen was not available. Therefore, we developed a sandwich enzyme-linked immunoassay (ELISA) to quantitate total IgG, IgA and IgM in seminal plasma from 16 healthy, nonvaccinated, adult boars (n= 102 semen samples). In seminal plasma, IgG was the predominant isotype followed by IgA and IgM. Mean levels ± the standard deviation followed by the 95% confidence interval of IgG, IgA and IgM were 23.2 ± 14 μg/mL (15.5 to 31.0), 4.8 ± 2.5 μg/mL (3.5 to 6.2) and 3.7 ± 1.7 μg/mL (2.7 to 4.7), respectively. These concentrations of immunoglobulins in seminal plasma were considerably lower than in other swine secretions, which might allow for the survival of infectious agents in boar semen.