ABSTRACT
Although T lymphocytes are the major mediators of protection against TB, high titers of antibodies with specificity for numerous proteinaceous and nonproteinaceous mycobacterial antigens can be measured in sera of patients (17-19). Such antibodies have several potential antimycobacterial functions. Antibodies may attack free-living MTB, although this is a rare situation because MTB mostly resides within MP. However, with dissemination of free MTB from the primary site of implantation to other tissue sites, the pathogen may be vulnerable to attack by antibodies (20). Antibodies could also synergize with phagocytes since antibody binding to the Fc-receptor can induce potent effector mechanisms, including generation of reactive oxygen and nitrogen intermediates (21,22). Finally, preexisting antibodies in the lung could clear the few bacteria that enter the host before they can hide within macrophages. A potential new vaccine approach would be to attempt to stimulate high titers of IgA and IgG antibodies capable of eliminating MTB promptly after its inhalation and prior to its engulfment by alveolar macrophages (23).
