Enhanced mucosal immune response in cattle persistently infected with foot-and-mouth disease virus.
The mucosal immune response to foot-and-mouth disease virus (FMDV) type Asia 1 was examined in experimentally infected cattle by assaying antibodies by the virus-neutralizing test (VNT) and IgA ELISA in two secretory fluids, oesophageal pharyngeal fluid (OPF) and oro-nasal fluid (ONF). Out of 17 animals infected by the intradermo-lingual route, 12 became persistently infected (carriers), as defined by positive antigen capture RT-PCR reactions for FMDV RNA in OPF samples collected at 28 days or later after exposure. This proportion of carriers (71%) with FMDV Asia 1 is comparable to other serotypes of the virus. When the two groups were examined, the carriers and non-carriers showed no difference in the serum antibody titre until the end of the experiment at 182 days post-infection (DPI). However, despite an initial similarity significantly higher neutralizing antibody titres and FMDV-specific IgA response were detected among the carriers than the non-carriers in both of the secretory fluids. The response was higher and more stable in ONF compared to OPF. Thus, mucosal antibody assays have the potential to be used as a means of differentiating carrier from non-carrier cattle. Furthermore, the findings are consistent with the higher mucosal antibody response in carriers being an effect of persistent infection rather than the cause.
Maddur
Mohan S
MS
Indian Veterinary Research Institute, Bangalore, Karnataka, India.
Mohan
Maddur S
MS
Gajendragad
Mukund R
MR
Kishore
Subodh
S
Chockalingam
Ashok K
AK
Suryanarayana
V V S
VV
Gopalakrishna
S
S
Singh
Nem
N
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002353:Carrier State / Q000276:immunology / Q000662:veterinary / Q000821:virology; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology* / Q000821:virology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005260:Female; D005536:Foot-and-Mouth Disease / Q000276:immunology* / Q000821:virology; D029544:Foot-and-Mouth Disease Virus / Q000235:genetics / Q000276:immunology*; D018928:Immunity, Mucosal / Q000276:immunology; D007070:Immunoglobulin A / Q000032:analysis; D008297:Male; D009297:Nasal Mucosa / Q000276:immunology / Q000821:virology; D009500:Neutralization Tests / Q000662:veterinary; D010614:Pharynx / Q000276:immunology / Q000821:virology; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary
D000914:Antibodies, Viral; D007070:Immunoglobulin A; D012367:RNA, Viral