#07-023

Complete

Date Full Report Received

01/25/2009

Date Abstract Report Received

01/25/2009

Investigation

Institution:
Primary Investigator:

Enzootic pneumonia resulting from Mycoplasma hyopneumoniae infections is an important disease to the US swine industry. Antibodies and immune cells specific to this agent can be detected after vaccination and dams can transfer this immunity to their piglets. It is necessary to understand how cross-fostering can affect passive transfer for Mycoplasma and the protective role of those immune components. Therefore, the objectives of this research were to examine the impact of cross-fostering on the transfer of maternally derived immunity against M. hyopneumoniae and influence of the transferred passive immunity on protection from virulent challenge. To examine the first objective, that of examining the effect of cross-fostering on immune transfer, the offspring of vaccinated and unvaccinated dams were cross-fostered at 0, 6, 12 and 20 hrs post-suckling (hps) and humoral and cell mediated immunity in the offspring was assessed. Anti-M. hyopneumoniae antibodies were transferred to piglets regardless of source, as long as the piglet was fostered prior to 6 hps. Immune cells were absorbed by piglets that suckled from their own mothers or by a small number of piglets, born from unvaccinated mothers, cross-fostered onto vaccinated sows within the first 6 hps. To evaluate the second objective, that of protection from challenge in piglets receiving different immune components, one-week old piglets passive administered either M. hyo specific immunoglobulin and/were challenged with a virulent strain of M. hyopneumoniae. Piglets were divided into groups regarding their status for immune components to Mycoplasma: (1) No immune components, (2)Immunoglobulins + cells, (3) Only immunoglobulins, (4) and only cells. Piglets with or without cells or antibodies were infected with the bacteria, showed coughing, shed the pathogen and had lung lesions associated with Mycoplasma. Animals born from vaccinated mothers appeared to shed the agent later and in a smaller proportion than the other groups, but differences were not statistically significant. The study indicates that M. hyopneumoniae-specific cellular immunity does not transfer into the piglet the same way as humoral immunity. Cross-fostering should be used judiciously and adequate time spent on the sow prior to cross-fostering is critical for successful transfer of immune components.