Klipstein F A, Engert R F, Clements J D
Infect Immun. 1981 Jun;32(3):1100-4. doi: 10.1128/iai.32.3.1100-1104.1981.
Rats immunized with Escherichia coli heat-labile (LT) enterotoxin, either in the form of the holotoxin derived from a transformed K-12 strain or the polymyxin-release form obtained from human strains which produce LT toxin alone (LT+/ST- [ST is heat-stable toxin)] or together with ST toxin (LT+/ST+), were challenged with viable organisms of 10 different serotypes, 5 LT+/ST- and 5 LT+/ST+. The serum antitoxin response was monitored by enzyme-linked immunosorbent assay, and the degree of protection was determined by challenge in ligated ileal loops. Immunization with the holotoxin provided a strong antitoxin response and protection against all 10 challenge strains. Immunization with toxin from the LT+/ST+ strain provided equally strong protection against all strains, but immunization with toxin from the LT+/ST- strain yielded only a weak antitoxin response, moderate protection against challenge with LT+/ST- strains, and no protection against LT+/ST- strains, increasing by fivefold the immunization dosage of the LT+/ST- toxin failed to enhance protection. These observations (i) establish the fact that immunization with the LT holotoxin provides uniformly strong protection against heterologous serotypes and (ii) indicate that, for reasons which remain to be determined, the immunogenicity of the polymyxin-release LT from an LT+/ST+ strain differs from that of an LT+/ST- strain.
用大肠杆菌不耐热（LT）肠毒素免疫大鼠，该肠毒素有两种形式，一种是源自转化的K - 12菌株的全毒素，另一种是从仅产生LT毒素（LT+/ST- [ST是耐热毒素]）或同时产生ST毒素（LT+/ST+）的人菌株获得的多粘菌素释放形式。用10种不同血清型的活生物体对大鼠进行攻击，其中5种为LT+/ST-型，5种为LT+/ST+型。通过酶联免疫吸附测定监测血清抗毒素反应，并通过在结扎回肠袢中进行攻击来确定保护程度。用全毒素免疫可产生强烈的抗毒素反应，并对所有10种攻击菌株提供保护。用LT+/ST+菌株的毒素免疫对所有菌株提供同样强的保护，但用LT+/ST-菌株的毒素免疫仅产生微弱的抗毒素反应，对LT+/ST-菌株攻击有中等程度的保护，对LT+/ST+菌株则无保护作用，将LT+/ST-毒素的免疫剂量增加五倍也未能增强保护作用。这些观察结果（i）证实了用LT全毒素免疫可对异源血清型提供一致的强保护这一事实，（ii）表明，由于尚待确定的原因，来自LT+/ST+菌株的多粘菌素释放LT的免疫原性与LT+/ST-菌株的不同。
