Idiotypes, T-cell receptors, and T-B cooperation

T cells are responsible for virtually all the characteristics of the mammalian immune system except the production of serum antibody, in which they play a vital regulatory role. As such, they are central to our understanding of the immune system. T cells recognize cell-bound antigens with great precision, in association with self MHC antigens. They do this by means of antigen-specific receptors, whose antigen-combining sites are encoded in conventional VH genes. There is evidence that T cells carry at least two kinds of specific receptors, one for MHC antigens and one for non-MHC antigens. Both of these would bear VH-encoded and distinct idiotypic determinants. The process by which antigens associate with MHC-gene products on cell surfaces is poorly understood at present, and so is the process by which the two types of receptors communicate with each other. T cells are divisible into a number of subpopulations playing unique functional roles in the regulation of antibody responses. If one examines them further for other functions, even greater complexity emerges. Thus, all T cells may not have the same kind of receptor, which would not be surprising given the wide variety of functions they perform. Future work will undoubtedly focus on these important questions.

Plague antibody in large African mammals

Plague hemagglutinating antibodies to a titer of 1:1,024 were demonstrated in 6.6% of buffalo and 0.3% of elephant sera tested 1 year after a plague epidemic in the same area.

Rocky mountain spotted fever in Connecticut: human cases, spotted-fever group rickettsiae in ticks, and antibodies in mammals

Three parameters were used in 1976 and 1977 to assess the status of Rocky Mountain spotted fever (RMSF) in Connecticut--compilation and review of clinical data on suspected human cases for the 13-year period 1965--1977, examination of tick tissues for spotted fever-group rickettsiae by the hemolymph test and direct immunofluorescence, and analyses of mammalian sera for antibodies against Rickettsia rickettsii. There were six presumptive RMSF cases which probably originated in Connecticut. Four of these cases occurred in areas where the American dog tick, Dermacentor variabilis, abounds. A total of 2994 ticks were examined by the hemolymph test. Rickettsia-like organisms were observed in 67 (2.9%) of 2330 D. variabilis and two (0.6%) of 351 Ixodes sp. near scapularis. Fewer than one-half of these organisms stained positively with spotted fever-group conjugate. Microagglutination tests on 1093 mammalian sera indicated that eight (16%) of 49 raccoons, 14 (2.6%) of 549 white-tailed deer, eight (1.7%) of 470 white-footed mice, and one of two gray squirrels had agglutinins in titers greater than or equal to 1:8 against R. rickettsii. Spotted fever-group rickettsiae are present at low frequency in inland as well as coastal regions of Connecticut.

Radioimmunoassay for quantitation of antibodies to alphaviruses with staphylococcal protein A

A radioimmunoassay (RIA) procedure is described for measuring antibodies to alphaviruses in human and other mammalian sera. The test employed protein Abearing Staphylococcus aureus as a solid-phase immunoadsorbent for (3)H-labeled viruses complexed with immunoglobulin G. Using antibodies produced in humans and guinea pigs, the RIA procedure clearly differentiated among antibodies to Venezuelan, western, and eastern equine encephalomyelitis viruses. Sensitivity of the RIA depended on the concentrations of labeled viruses employed. The dilution of serum that effected binding of 50% of the (3)H-labeled virus (determined by probit analysis) was consistently higher than the neutralizing antibody titer determined by a conventional plaque reduction neutralization test using 80% plaque reduction end points. In addition, sera from 73 individuals were screened for seroconversion following live attenuated Venezuelan equine encephalomyelitis virus vaccine (strain TC-83) inoculation, by RIA using a single serum dilution (1:80); results were identical with seroconversions identified by plaque reduction neutralization test. Hyperimmune Venezuelan equine encephalomyelitis virus sera from a number of mammalian species were successfully titrated by RIA; the species tested were human, guinea pig, white rat, rabbit, burro, dog, monkey, sheep, and cotton rat. The protein A-mediated RIA is a rapid, sensitive, specific, and precise serological tool for measuring antibodies to surface antigens of alphaviruses, and should allow the subsequent development of a competitive binding RIA to measure antigenic potency of inactivated alphavirus vaccines.

Antibody diversity in amphibians: inheritance of isoelectric focusing antibody patterns in isogenic frogs

Anti-sheep red cell, anti-dinitrophenyl, anti-phosphorylcholine antibody responses have been followed in isogenic frogs of the genus Xenopus. Isoelectric focusing antibody patterns show a high degree of overlap for all antigens studied, and a heterogeneity that is lower than in mammals for the same antigens. Inheritance of antibody isoelectric focusing spectrotypes was demonstrated for sheep red cells and dinitrophenyl in two clones of isogenic animals. Outbred frogs show a higher frequency of spectrotype sharing than outbred mammals. It is therefore suggested that antibody diversity is lower in frogs than in mammals.

Prevalence of vesicular exanthema of swine antibodies among feral mammals associated with the southern California coastal zones

Serum-neutralizing antibodies to both vesicular exanthema of swine virus (VESV) and San Miguel sea lion virus (SMSV) were found in a number of animal species having an association with the southern California coastal zones. California sea lions (Zalophus californianus) had antibodies to 9 VESV types (A48, C52, D53, E54, F54, G55, I55, J56, and K56). Fur seals (Callorhinus ursinus) and elephant seal pups (Mirounga angustirostris) were tested for antibodies to 6 VESV types and all were negative. California gray whales (Eschrichtius robustus) were tested for antibodies to 9 VESV types, and sperm whale (Physeter catodon), finback whale (Balaenoptera physalus), and sei whale (Balaenoptera borealis) were tested for 6 VESV types. Among the last 4 species, antibodies were present for each VESV type except C52, and all species were positive for antibodies to 2 or more VESV types. Feral swine from both Santa Cruz Island and Santa Catalina Island were tested and antibodies were present for 8 of 9 VESV types and all SMSV types except SMSV-4. One donkey from San Miguel Island was positive for VESV I55 and 2 were positive for SMSV-2.

Human poxvirus disease after smallpox eradication

A 5-year-old boy living in a small camp in the rural Ivory Coast had a disease resembling smallpox. This occurred 4 years after smallpox had been eradicated from the Ivory Coast and 1.5 years after the last case of smallpox was detected in West and Central Africa. Clinical, serological, and epidemiological evidence indicated this disease was probably monkeypox, a poxvirus of the variola/vaccina subgroup. A serologic survey of poxvirus antibodies in the wild animal population detected neutralizing antibodies in rodents, larger mammals, primates, and birds. The laboratory and ecological characteristics of poxviruses require further elucidation, especially those which have been found in animals near human monkeypox cases.

Plasma cells in vertebrate paraocular glands

The Harderian and lachrymal glands of eight mammals and two reptiles were examined histologically for plasma cells and the extent of infiltration compared to that in the Harderian gland of the fowl. Moderate accumulations were observed in one or both glands of the goat, sheep, cow, horse, dog and pig, but only few cells were present in the glands of the mouse and rabbit. No plasma cells were encountered in snake glands but some were detected in both glands of lizards. It is suggested that glandular secretions contribute to local immunity.

Endemic eastern equine encephalomyelitis in Florida: a twenty-year analysis, 1955-1974

Research and surveillance programs relating to the circulation of eastern equine encephalomyelitis (EEE) virus in Florida between 1955 and 1974 are summarized. All available data suggest that EEE virus is 1) endemic in many Florida fresh water swamps and waterways, 2) active in a continuous cycle throughout the year with a peak between May and August, and 3) circulating in Culiseta melanura. It has been isolated also from eight other mosquito species.

Leptospirosis in small mammals of Iran: I. Serologic tests and isolation of Leptospira hebdomadis from Apodemus sylvaticus

Leptospires of the hebdomadis sero-group and related to sejroe serotype, were isolated from the kidney of a vole (Apodemus sylvaticus) by direct culture as well as by animal inoculation. Sera of the vole from which leptospires were isolated, and serologic specimens from 1372 other small mammals, were negative for leptospiral agglutinins.

Toxoplasma gondii antibodies in free-living African mammals

Twelve species of free-living African mammals from Kenya, Tanzania, Uganda and Zambia were tested for antibodies to Toxoplasma gondii using the indirect hemagglutination test. Of 157 animals sampled, 20 (13%) were seropositive. T. gondii antibodies were detected in Burchell's zebra, (Equus burchelli), hippopotamus (Hippopotamus amphibius), African elephant (Loxodonta africana), defassa waterbuck (Kobus defassa), lion (Panthera leo), and rock hyrax (Procavia capensis), The highest titers were found in elephants, two having titers of 1:4096 and one of 1:8192. These results are discussed in relation to the maintenance of T. gondii among African wildlife.