Specific mucosal IgA immunity in turkey poults infected with turkey coronavirus

Abstract

The objective of this study was to elucidate the kinetics and magnitudes of specific IgA antibody responses in intestines of turkey poults infected with turkey coronavirus (TCV). Turkey poults were orally inoculated with TCV at 10 days of age. Intestinal segment cultures were administered for duodenum, jejunum, and ileum and the IgA antibody responses were analyzed at 1, 2, 3, 4, 6, or 9 weeks post-infection (PI) in two different experiments. The kinetics of virus-specific IgA antibody responses in duodenum, jejunum, and ileum were similar: gradually increased from 1 week PI, reached the peak at 3 or 4 weeks PI, and declined afterward. The virus-specific IgA antibody responses in duodenum, jejunum, and ileum showed negative correlation with duration of TCV antigen in the corresponding locations of intestine with Spearman's correlation coefficient of -0.85 (p=0.034), -0.74 (p=0.096), and -0.75 (p=0.084), respectively. Moreover, the virus-specific IgA antibody responses in serum were positively correlated with that of duodenum (coefficient=0.829, p=0.042), jejunum (coefficient=0.829, p=0.042), and ileum (coefficient=0.771, p=0.072) segment cultures, suggesting that the induction of specific IgA response in serum was predictive of an IgA response in intestine. The results indicate that intestinal mucosal IgA antibodies to TCV are elicited in turkeys following infection with TCV. The local mucosal antibodies may provide protective immunity for infected turkeys to recover from TCV infection.

Pulmonary and serum antibody responses elicited in zebu cattle experimentally infected withMycoplasma mycoidessubsp.mycoidesSC by contact exposure

“…Similarly, a positive correlation between M. gallisepticum-specific IgA titers in tracheal secretions and decreased lesions caused by the organism has been reported [2]. Our results which are consistent with these reports and similar studies conducted on other mucosal infections [7,11], strongly suggest a potential role for the local IgA in the protective mechanism against MmmSC infection. Whether this role is to block MmmSC attachment to host mucosal surface or to help killing MmmSC by enzymes or other substances within mucosal secretions remains to be determined [19].…”

Early Detection of Antibodies against Various Structural Proteins of the SARS-Associated Coronavirus in SARS Patients

“…Therefore, the synthesis of specific IgA antibodies in the early stage of a SARS-CoV infection is reasonable, and this phenomenon was also observed in other studies related to coronaviruses [4,10,12]. For example, Loa et al [10] reported that the specific IgA antibodies against a turkey coronavirus were initially detected in serum 1 week after oral inoculation; these gradually increased and reached a peak at week 4 and finally declined at weeks 6-9. Furthermore, we noted that all three classes of immunoglobulins reacted with N and S antigens, but the antibody response of IgM to S antigen was much lower than that of IgA or IgG.…”

“…Not only do cellular immune responses result from mucosal infection by intracellular pathogens, but also secretory IgAs are produced to function as another important defense mechanism against invasion of deeper tissues by these pathogens [18]. Therefore, the synthesis of specific IgA antibodies in the early stage of a SARS-CoV infection is reasonable, and this phenomenon was also observed in other studies related to coronaviruses [4,10,12]. For example, Loa et al [10] reported that the specific IgA antibodies against a turkey coronavirus were initially detected in serum 1 week after oral inoculation; these gradually increased and reached a peak at week 4 and finally declined at weeks 6-9.…”

Complete nucleotide sequence of polyprotein gene 1 and genome organization of turkey coronavirus

“…The presence of TCoV in the intestines of embryos was confirmed by TCoV-specific immunofluorescence antibody assays and electron microscopy at the Indiana State Animal Disease Diagnostic Laboratory in West Lafayette, IN, USA (Lin et al, 2004). Viruses were purified from small intestine following published method (Loa et al, 2002) and either used immediately or stored at −80 • C for further use.…”