Th1/Th2 polarization by viral and helminth infection in birds.
Mammals developed an immune system able to functionally polarize into so-called type 1 or type 2 immune pathways, to resolve infections with intracellular and extracellular pathogens, respectively. In the well-studied avian immune system of the chicken, however, no evidence for polarized immunity could be found, as yet. To investigate whether these two major arms of mammalian immunity, regulated by a T helper (Th)1/Th2 cytokine balance, evolved similarly in birds, chickens were exposed to a prevalent intracellular (viral) or extracellular (helminth) infection. By using semi-quantitative RT-PCR analysis we provide evidence that polarization of Th1/Th2 type immunity extends beyond mammalian species, and, therefore, has been evolutionary conserved for more than 300 million years, when the lineages of mammalian and avian vertebrates are assumed to have segregated.
Degen
Winfried G J
WG
Department of Vaccine Technology and Immunology, Intervet International BV, P.O. Box 31, 5830 AA Boxmeer, The Netherlands.
Daal
Nancy van
Nv
Rothwell
Lisa
L
Kaiser
Pete
P
Schijns
Virgil E J C
VE
D000818:Animals; D001197:Ascaridia / Q000276:immunology; D001198:Ascaridiasis / Q000276:immunology / Q000662:veterinary*; D001483:Base Sequence; D005075:Biological Evolution; D002645:Chickens / Q000276:immunology*; D016207:Cytokines / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D007082:Ileum / Q000276:immunology; D007111:Immunity, Cellular; D009521:Newcastle Disease / Q000276:immunology*; D009522:Newcastle disease virus / Q000276:immunology; D011201:Poultry Diseases / Q000276:immunology* / Q000469:parasitology / Q000821:virology; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology* / Q000378:metabolism; D018418:Th2 Cells / Q000276:immunology* / Q000378:metabolism
D016207:Cytokines; D012333:RNA, Messenger