Takahashi H, Zhu S W, Ijichi S, Vahlne A, Suzuki H, Hall W W
Division of Infectious Diseases, North Shore University Hospital, Cornell University Medical College, Manhasset, New York 11030.
AIDS Res Hum Retroviruses. 1993 Aug;9(8):721-32. doi: 10.1089/aid.1993.9.721.
A study by Hall et al. (J Virol 1992;66:2456-2463; Ref. 11) has suggested the existence of two closely related molecular subtypes of HTLV-II, which were tentatively designated HTLV-IIa and HTLV-IIb. To confirm this nucleotide sequence analysis of 986 bp of the env gene region encoding the entire surface glycoprotein, gp46, and the amino terminus of the transmembrane glycoprotein, gp21, of 10 HTLV-II isolates was carried out. The results clearly established the existence of two subtypes and demonstrated a 4.3% divergence in sequence in this region. Analysis of other gene regions of the provirus, including the pol (1544 bp), gag (448 bp), and the entire LTR (743 bp) of two representative isolates of each subtype, showed a sequence divergence of 3.8 to 5.7%, with greatest divergence occurring in the LTR. In addition to single nucleotide changes, the gag regions encoding the structural protein, p19, of the HTLV-IIb isolates were also found to have a 66-bp deletion that would be expected to result in a p19 protein having a 22-amino acid deletion in the carboxy-terminus region. Attempts to exploit this to differentiate the two subtypes serologically were unsuccessful in that recombinant p19 proteins of both subtypes were found to be antigenically cross-reactive. The finding of two molecular subtypes of HTLV-II may have important implications for a better understanding of the biological and pathogenic properties of the virus, and will be useful in characterizing the viruses present in endemic foci in American Indian populations.
霍尔等人的一项研究（《病毒学杂志》1992年；66:2456 - 2463；参考文献11）表明，人类嗜T淋巴细胞病毒II型（HTLV-II）存在两种密切相关的分子亚型，暂定为HTLV-IIa和HTLV-IIb。为证实这一点，对10株HTLV-II分离株的env基因区域进行了986 bp的核苷酸序列分析，该区域编码整个表面糖蛋白gp46以及跨膜糖蛋白gp21的氨基末端。结果清楚地证实了两种亚型的存在，并表明该区域的序列差异为4.3%。对每种亚型的两个代表性分离株的前病毒其他基因区域进行分析，包括pol（1544 bp）、gag（448 bp）和整个长末端重复序列（LTR，743 bp），结果显示序列差异为3.8%至5.7%，其中LTR的差异最大。除了单核苷酸变化外，还发现HTLV-IIb分离株中编码结构蛋白p19的gag区域有一个66 bp的缺失，预计这会导致p19蛋白在羧基末端区域有22个氨基酸的缺失。试图利用这一点通过血清学方法区分这两种亚型未获成功，因为发现两种亚型的重组p19蛋白具有抗原交叉反应性。HTLV-II两种分子亚型的发现可能对更好地理解该病毒的生物学和致病特性具有重要意义，并且将有助于鉴定美洲印第安人群地方性疫源地中存在的病毒。
