Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/19/2002
Publication Date: 5/1/2003
Citation: CRIPPEN,T.L., BISCHOFF,K.M., LOWRY,V.K., KOGUT,M.H., RP33 ACTIVATES BACTERIAL KILLING BY CHICKEN PERIPHERAL BLOOD HETEROPHILS, JOURNAL OF FOOD PROTECTION, 66(5):787-792, 2003.
Interpretive Summary: The presence of Salmonella bacteria in food is the cause of an estimated 500 deaths every year in the United States. Chicken products are a known source for Salmonella bacteria. Reducing the numbers of bacteria in chickens will lead to improved human health as the bacteria will not then be passed on to humans. We have isolated a protein, which we call P33 that is able to reduce the number of bacteria in chickens. This study was designed to explore how P33 causes that decrease in the number of bacteria. We investigated how a particular chicken blood cell, called a heterophil, reacts when it is exposed to P33. Heterophils are important for destroying bacteria that enter the body. We found that P33 helps heterophils destroy bacteria. This is important to the poultry industry because it could help us raise chickens with less Salmonella and therefore decrease sickness and death related to contaminated chickens.
Technical Abstract: Salmonella immune lymphokine (SILK), produced by stimulated splenic T cells from Salmonella enteritidis (SE)-immunized chickens, has been shown to confer protection against Salmonella infection in day old chicks. The SILK induced protection is mediated through a heterophil response and the protection can be neutralized by polyclonal antibodies to human granulocyte colony stimulating factor. This antibody primarily binds a 33kDa protein, identified as P33, the product of the chicken mim-1 gene. We previously produced a recombinant derivative of mim-1 expressing a domain of P33 that is chemotactic for heterophils. We report here that the P33 recombinant protein (rP33) also possesses activation capabilities directed toward heterophils in vitro. The killing of SE by heterophils was increased by rP33 treatment. Such treatment up regulated phagocytosis and directly stimulated degranulation of heterophils. However, rP33 did not induce an oxidative burst in heterophils. These results are evidence that P33 is an active component of Salmonella immune lymphokine conferring protection against SE by augmenting antimicrobial activities of heterophils.