Delayed type hypersensitivity theilerin test in cattle vaccinated against Theileria annulata infection.

Theilerin was prepared and its total nitrogen was determined at level of 1 mg/ml. Seventy-two Holstein Friesian cattle recovered from acute theileriosis or vaccinated received 0.1 ml of theilerin intradermally at normal concentration of total nitrogen or other dilutions (1 / 10 and 1 / 100). Some 60(% of calves and 66.67% of milking cows receiving normal theilerin showed more than 1 mm increase in skin thickness at the site of inoculation (mean value of 1.86 mm for calves and 3.46 mm for milking cows). The pathological examination of the inoculation site showed infiltration of lymphocytes. No changes of general condition were observed in animals under study. The result indicated that the test is positive and could be used for checking Immunity in vaccinated animals.

Stimulating role of toxoids-laden liposomes in oral immunization against diphtheria and tetanus infections.

Liposomes have been produced by injecting an ether solution of a mixture of lecithin and cholesterol into a diluted solution of prewarmed diphtheria and tetanus toxoids followed by elimination of the stream of ether vapour by vacuum. In a preliminary study, adjuvant effects of liposomes on the systemic and mucosal immune response have been studied. When a mixture of diphtheria toxoid (DT) and tetanus toxoid (TT) entrapped in liposomes were administered parenterally or orally in rabbit, a significant rise of specific antibodies against both toxoids was noticed. In monkeys receiving a mixture of DT and TT entrapped in liposomes orally, the antibody response after two and three ingestions of this product was mild but when liposomes containing toxoids were adsorbed with aluminium hydroxide in a similar experiment, a significant rise in the specific antibody response in monkey against both toxoids was recorded. Adult volunteers, similarly receiving a mixture of DT and TT, entrapped in liposomes and adsorbed with aluminium hydroxide have shown a significant rise in specific circulating antitoxins. In order to compare the efficacy of this technique of human oral immunization with the previous method, whereby a plant medicinal seed (LRS) was used as adjuvant in oral immunization of man, a second group of volunteers were simultaneously and similarly treated as suggested previously. The comparative results are discussed in the present report.

Cryptosporidium spp. in new born lambs in Iran.

In a study conducted to investigate the causes of the death of new born lambs due to diarrhoea 237 cases were studied. In 16 of these lambs necropsied at four to 10 days old organisms considered to be Cryptosporidia at various stages of its life-cycle were associated with the luminal surface of the epithelium of the intestinal tract. The histopathology and the mechanism of the diarrhoea caused by the parasite and the resulting deaths are discussed.

Isolation and characterization of a defective measles virus from brain biopsies of three patients in Iran with subacute sclerosing panencephalitis.

Three cytopathic strains of subacute sclerosing panencephalitis (SSPE) virus were isolated from brain biopsies of three patients. These strains were isolated and maintained by cocultivation of infected brain cells with fresh Vero cells. The biological characteristics of two strains were studied. It was found that these strains remain cell-associated after repeated cocultivations with Vero cells and produce plaques under fluid medium or tragacanth overlay. The correlation with measles virus was demonstrated by the plaque reduction test as well as by the immunofluorescence test. Large numbers of nucleocapsids were observed in the cytoplasm of infected cells but none in nuclei. Intracerebral inoculation of monkeys, adult guinea pigs, newborn and adult hamsters or mice was followed by acute encephalitis and death.

Development of a new live attenuated mumps virus vaccine in human diploid cells.

A new live attenuated mumps vaccine was developed in human diploid cells. The S-12 virus was isolated from a 10-year-old girl showing typical symptoms of mumps infection, the diagnosis was confirmed by a pediatrician. The virus was isolated in green monkey kidney cells, without passage in chick embryo cavity or chick embryo fibroblasts. Attenuation of the wild virus was performed by serial passages in human diploid cells (MRC-5). The attenuated virus was characterized by identity tests, as well as by a reduction in plaque size, as marker tests. The virus was free from adventitious agents and safe for laboratory animals as well as for monkeys. The reactogenicity and immunogenicity of the S-12 virus for man was investigated by administration of a monovalent vaccine to 20 seronegative adult male volunteers and 30 children aged 1 to 5 years without history of mumps infection or vaccination. Seroconversion was obtained in 95% of the vaccinees. The new vaccine has the advantage of not requiring specific pathogen-free eggs, and being free from avian proteins and therefore can be used in sensitized patients.