This effect might be due to SIgA as previous studies have shown that mice that have no secretory antibody response (pIgR-/-) are more susceptible to infections with virulent strains [68], and also that infections with Salmonella strains that are unable to be bound by SIgA result in higher levels of colonisation in systemic organs than SIgA sensitive strains [69]. The gene discussed is PIGR; the disease is infection.