CD40LG and tuberculosis: The immunodeficient mice, lacking IgM secretion, exhibit significant susceptibility to TB, indicating the protective role of IgM in TB progression (99, 102) Intravenous administration of the BCG vaccine can prevent Mtb infection in a rhesus monkey model (100), and the existence of Mtb-specific IgM in bronchoalveolar lavage fluids (BALF) of the BCG-vaccinated monkeys implies that IgM can have protection against TB in an early phase of Mtb-host interaction (98, 100).