Anti-idiotypic antibodies against a monoclonal antibody specific for the trichothecene mycotoxin T-2

A BALB/c murine monoclonal antibody against the trichothecene mycotoxin T-2 was generated. The antibody, designated HD11, specifically bound T-2 mycotoxin. The binding of HD11 to T-2 conjugated to bovine serum albumin was inhibited by free T-2 toxin but not by the water-soluble heterocyclic guanidines saxitoxin and tetrodotoxin. The T-2 detection limit in an enzyme-linked immunosorbent assay with HD11 was in the nanogram range. The in vitro cytotoxicity of T-2, as measured by the inhibition of radiolabeled leucine uptake of the human epidermoid carcinoma Hep-2 and KB cell lines, was completely reversed by the addition of HD11. Rabbit anti-idiotypic antibodies specific for HD11 were generated and characterized.     

Streptococcus pyogenes bacteraemia: an old enemy subdued, but not defeated

Bacteraemia with Streptococcus pyogenes (Group A haemolytic streptococci) was reviewed in patients admitted to University Hospital, Nottingham over a period of 7 years. Altogether, 40 cases were encountered, representing 2% of all cases of bacteraemia. Mortality was 35%. Most cases were community-acquired and 28% of patients were less than 40 years of age. A third of the patients were previously fit. The most common sources of bacteraemia were the skin and soft tissue (23 patients) and the respiratory tract (eight patients). Shock was recorded in 40% of cases and carried a 60% mortality. This feature of streptococcal bacteremia has not received sufficient attention in the past. Despite its unique susceptibility to penicillin, S. pyogenes continues to pose a challenge to the physician.     

Monoclonal Antibody Prophylaxis Against the in Vivo Toxicity of Ricin in Mice

A BALB/c murine IgG₁ monoclonal antibody, designated BG11-G2, specific for ricin was generated. BG11-G2 antibody did not bind to either purified ricin chain A or chain B, but recognized an antigenic determinant whose conformation requires the combination of the two chains in the formation of the native ricin molecule. It did not react with the protein synthesis inhibitor, T-2 mycotoxin, or with the sodium channel blockers, saxitoxin and tetrodotoxin. As little as 0.78 μg/ml of BG11-G2 IgG₁ anti-ricin monoclonal antibody completely protected against the in vitro toxicity of ricin as determined by [³H]leucine uptake in EL-4 cell assays. Passive intraperitoneal infusion of purified BG11-G2 antibody into BALB/c mice one day prior to a lethal challenge with ricin considerably delayed the onset of toxicity and death. Better protection was obtained with BG11-G2 infused before and after ricin challenge.     

Infectious mononucleosis and the Epstein-Barr virus.

Recent elucidation of the relationship between the Epstein-Barr virus and infectious mononucleosis has resulted in the development of new diagnostic serological tests, and has amplified our knowledge of the epidemiological and clinical aspects of the disease. The history, epidemiology, clinical characteristics, diagnostic features, and therapy of infectious mononucleosis are reviewed. This is done in the light of recent knowledge concerning the Epstein-Barr virus as well as previous studies employing the traditional diagnostic criteria of heterophil positivity, the classical clinical symdromes, and characteristic changes in the blood cell count. Immunological studies concerning host resistance and its occasional failure are reviewed with particular reference to T and B lymphocyte activity in the disease.     

Anti-idiotype-based vaccines against biological toxins

Biological toxins produced by living organisms represent one of the major sources of contamination of stored grain and agricultural products, and other food sources. The majority of these biological toxins are highly lethal, nonproteinaceous low-molecular-weight chemical compounds which exert their potent toxicity through a variety of mechanisms. Because of their small size, they generally do not induce a significantly high affinity protective antibody response upon toxin exposure, even when conjugated to large protein carriers which enhance their immunogenicity. Moreover, the very toxic nature of biological toxins precludes their use as immunogens in the induction of protective immunity. To circumvent this difficulty, an attempt was made to develop antibody (anti-idiotype)-based vaccines against a protein synthesis inhibitor, the trichothecene mycotoxin T-2, and the sodium channel blockers tetrodotoxin and saxitoxin. Protective monoclonal antitoxin antibodies were first generated and then used to induce specific monoclonal anti-idiotype antibodies. Specific anti-idiotype antibodies were assessed for their ability to induce in vivo protective immunity against toxicity.