INDUCIBLE PREPROTACHYKININ MESSENGER-RNA EXPRESSION IN MUCOSAL LYMPHOID ORGANS FOLLOWING ORAL IMMUNIZATION WITH SALMONELLA

Using a sensitive and specific reverse transcribed-polymerase chain reaction (RT-PCR), it was possible to quantify relative increases in preprotachykinin (PPT) mRNA expression in vivo following oral administration of Salmonella. Despite the presence of constitutive levels of PPT mRNA expression in the Peyer's patches, expression of this mRNA increased within 20 h following oral administration of Salmonella. Increases in PPT mRNA expression were also detected in both the mesenteric lymph nodes and spleens following Salmonella administration despite the lack of constitutive PPT mRNA expression in these lymphoid organs. Furthermore, mononuclear leukocytes contributed to this increased expression of PPT mRNA, suggesting that the initial immune response against Salmonella occurs in the presence of increased tachykinin expression.