Regarding studied pigs, anti-ORF1-A IgG SR1078 were observed in sera of conventional pigs, suggesting that the host immune system is producing anti-TTSuV1 and TTSuV2 antibodies against ORF1 or their splice variants. The production of anti-TTSuV antibodies was expected based on previous studies in swine populations, but also in humans (Handa et al., 2000, Huang et al., 2011 and Huang et al., 2012). Although pigs developed antibodies against TTSuVs, they were not clearing out the viral infection since until end of the study these viruses were detected in sera by qPCR. It is known that anelloviruses cause persistent infections and may use different mechanisms to evade immune system, like high mutation rate, presence of multiple variant infecting single host or recombination (Cortey et al., 2011 and Jelcic et al., 2004). In the present study, one piglet did not seroconvert although it was TTSuV2 infected. A previous study on TTSuVs showed that a proportion of animals may become infected before the immune system matures (Aramouni et al., 2010). Such animals are likely to get immunotolerant to TTSuV. However, more work on this field would be needed in order to confirm such hypothesis.
↧