Immunity after PRRSV infection and after vaccination

The immune response after vaccination is similar to that after a natural PRRS infection.

After infection

PRRSV-specific antibodies can persist for more than one-year post infection. Maternally derived antibodies (MDA) against PRRSV usually disappear by 6 weeks of age. Most reports indicate that MDA have a protective effect.

After vaccination

The humoral response can usually be detected from two weeks after vaccination. Typically the first neutralizing antibodies appear from 4 weeks onwards.The timing of the humoral response may be influenced by the strain of virus used and differences in the immune respponse of individual animals. Maximum antibody titres are usually obtained at approximately 4 weeks after vaccination. A cellular response, as seen after infection with PRRS field virus, can also be shown after vaccination . Vaccination with Porcilis PRRS, both intramuscular (Group 1) and intradermal (Group 2), stimulates the peripheral lymphocyte subpopulation, compared with a not vaccinated pigs (Group 3) (Borghetti at al. 2003).

immunity after vaccination - graph 1

Peripheral lymphocytes subpopulations (CD4+Th)

immunity after vaccination - graph 2

Peripheral lymphocytes subpopulations (CD8+ cells)