Kitaura H, Ohara N, Naito M, Kobayashi K, Yamada T
School of Dentistry, Nagasaki University, Sakamoto, Nagasaki City, Japan.
APMIS. 1998 Sep;106(9):893-900.
The alpha antigen, which is a 30 kDa protein secreted by mycobacterial species, is an immunodominant antigen. The C-terminal regions of alpha antigens are highly divergent, though there are regions where the amino acid sequence of alpha antigen is conserved. We investigated whether the C-terminal regions of the Mycobacterium avium alpha antigen, M. intracellulare alpha antigen and M. tuberculosis alpha antigen contain sequence-specific B-cell epitopes. The C-terminal regions of M. avium alpha antigen and M. intracelluare alpha antigen reacted to anti-M. avium alpha antigen but not to anti-M. tuberculosis alpha antigen derived from rabbits. Thus, M. avium and M. intracellulare have an antigenic determinant in common with rabbit. The C-terminal region of M. tuberculosis alpha antigen did not react to anti-M. avium alpha antigen or anti-M. tuberculosis alpha antigen. An enzyme-linked immunosorbent assay revealed that only the C-terminal region of M. avium alpha antigen reacted to the sera of two of six patients with M. avium-intracellulare (MAC) but not to the sera of patients with M. tuberculosis. In contrast, the C-terminal regions of M. intracellulare alpha antigen and M. tuberculosis alpha antigen were not recognized by the sera from patients with MAC or M. tuberculosis. This region of M. avium alpha antigen can produce a sequence-specific B-cell epitope in humans.
α抗原是分枝杆菌属分泌的一种30 kDa蛋白，是一种免疫显性抗原。α抗原的C端区域高度不同，不过也存在α抗原氨基酸序列保守的区域。我们研究了鸟分枝杆菌α抗原、胞内分枝杆菌α抗原和结核分枝杆菌α抗原的C端区域是否含有序列特异性B细胞表位。鸟分枝杆菌α抗原和胞内分枝杆菌α抗原的C端区域与抗鸟分枝杆菌α抗原发生反应，但不与源自兔的抗结核分枝杆菌α抗原发生反应。因此，鸟分枝杆菌和胞内分枝杆菌与兔有共同的抗原决定簇。结核分枝杆菌α抗原的C端区域不与抗鸟分枝杆菌α抗原或抗结核分枝杆菌α抗原发生反应。酶联免疫吸附测定显示，只有鸟分枝杆菌α抗原的C端区域与6例鸟分枝杆菌-胞内分枝杆菌（MAC）患者中的2例血清发生反应，而不与结核病患者的血清发生反应。相反，胞内分枝杆菌α抗原和结核分枝杆菌α抗原的C端区域未被MAC患者或结核病患者的血清识别。鸟分枝杆菌α抗原的该区域可在人体内产生序列特异性B细胞表位。
