Phagocytosis of TB bacilli does not occur because of-
Ans. is 'c' i.e., Cord factor o Virulent strains of tubercle bacilli form microscopic "serpentine cord" in which acid fast bacilli are arranged in parallel chains, cord formation is correlated with virulence. A "cord factor" has been extracted from virulent bacilli with pateroleum ether. It inhibits migration of leukocytes, causes chronic granulomas, and can serve as an immunologic "adjuvant".
Wax D
Muramyl dipeptide
Cord factor
Peritrichate Cilia