Estrogen in autoimmunity: expression of estrogen receptors in thymic and autoimmune T cells.

OBJECTIVE: To identify the targets of estrogen in immune system lymphocytes and to examine gender differences in autoimmunity. DESIGN: RNA samples from purified lymphocyte subsets were analyzed for the presence of mRNA for estrogen receptor alpha and beta (ER alpha and ER beta). Groups of male, female, and testicular-feminized mice were compared for autoantibody production. SUBJECTS: Autoimmune-prone lpr (Fas-deficient), testicular-feminized (Tfm, androgen receptor-deficient) and wild-type mice were studied. METHOD: Lymphocyte subsets were purified by fluorescence-activated cell sorting (FACS) and RNA was assessed for the presence of estrogen receptor sequences using specific oligonucleotide primers and the reverse transcription-polymerase chain reaction (RT-PCR). Spontaneous and induced antibody production in mice was determined by enzyme-linked immunosorbent assay (ELISA). RESULTS: ER alpha was expressed in all lymphocyte subsets examined. ER beta was expressed at low levels in thymic CD4/CD8- T cells in wild-type mice and at high levels in the peripheral CD4-/CD8- T cells in lpr mice. Both spontaneous and induced autoantibody production was higher in female lpr mice than in male lpr mice. CONCLUSIONS: The presence of ERs in lymphocytes indicates that estrogen may affect immune cells during their development and mature function. The selective expression of ER beta may help explain some of the physiological effects of estrogen and its pharmacologic analogues and may lead to means to direct estrogen analogues to such cells. Such effects may be explored in lpr mice, given the enhanced capacity of female lpr mice for autoantibody production.

Cross-reactivity of alternate plant sources of latex in subjects with systemic IgE-mediated sensitivity to Hevea brasiliensis latex.

BACKGROUND: Previous studies have suggested that there is cross-reactivity in subjects sensitive to natural rubber proteins with other plant proteins such as banana, chestnut, and avocado. There are numerous other plants known to produce rubber including Parthenium argentatum and Ficus elastica. It is not known whether patients with IgE-mediated systemic reactions caused by the common source of natural rubber Hevea brasiliensis are also sensitive to the rubber-containing material from these other plant sources of latex. It is also not certain how much the allergenicity of latex made from Hevea brasiliensis can be reduced by extracting proteins from the sap since some proteins are tightly associated with the cis-1,4-polyisoprene. OBJECTIVE: In this study we investigated whether there would be cross-reactivity to other natural sources of latex in these patients. METHODS: Seven patients with histories of systemic type I hypersensitivity to latex products had strongly positive skin tests to Hevea brasiliensis latex from two different sources. These subjects were tested by the prick method for sensitivity to three other natural sources of latex. These included latex-containing material from Parthenium-argentatum and Ficus elastica as well as washed and centrifuged rubber particles from Hevea brasiliensis sap. RESULTS: All subjects had negative skin tests to all dilutions of the rubber samples from these other natural sources of latex. CONCLUSION: These results suggest several potential sources of natural hypoallergenic latex that might be tolerated by latex-sensitive individuals.

Ecology of porcupines (Erethizon dorsatum) and Colorado tick fever virus in Rocky Mountain National Park, 1975-1977.

The involvement of porcupines, Erethizon dorsatum (L.), in the ecology of Colorado tick fever (CTF) virus in Rocky Mountain National Park was investigated from 1975 to 1977. Porcupine dens and feeding activity were found mostly on rocky knolls or on south-facing slopes within open stands of the montane coniferous forest, and 20 adult porcupines were trapped or captured by hand at those locations. An average of 24.6 +/- 5.4 adult Dermacentor andersoni Stiles ticks were found per animal (annual range, 17.5-31.4 ticks). The minimum CTF virus infection rate of the ticks removed from porcupines varied from 129 to 257, whereas for questing adult D. andersoni ticks from the same geographic area was 205 in 1976. No virus was isolated from the 20 animals, but 85% had neutralizing antibody against CTF virus. Porcupines utilize the same habitats described for the CTF ecosystem in Rocky Mountain National Park and appear to be an important host for adult D. andersoni.

Diagnosis and "desensitization" in tetanus vaccine hypersensitivity.

A 5-year-old boy was evaluated for a history of an anaphylactic reaction to a DPT immunization at 18 months of age. Cutaneous tests and RAST disclosed high titers of IgE antibody to tetanus toxoid vaccine. Variable sensitivity to different vaccine commercial preparations was demonstrated. Immunization was achieved using a 9-step graded dosing schedule with the tetanus toxoid vaccine to which the patient was least sensitive.

Powassan virus in Ixodes cookei and Mustelidae in New England.

Powassan virus was recovered from a pool of 3 nymphal and 1 adult female Ixodes cookei removed from a striped skunk (Mephitis mephitis) trapped in Massachusetts during 1967 and from a pool of 9 nymphal I. cookei from a long-tailed weasel (Mustela frenata) captured in Connecticut during 1978. Virus was detected in the blood of both mammals. Hemagglutination-inhibiting (HI) antibody to Powassan virus was demonstrated in 16.0% of the skunks sampled in Connecticut, and neutralizing antibody was detected in 83.3% of the skunks tested from Massachusetts. HI antibody was found in 1 of 6 long-tailed weasels from Connecticut and 1 of 6 short-tailed weasels (Mustela erminea) from Maine.

Discriminant analysis: a method of identifying foci of vector-borne diseases.

Identification of foci of vector-borne diseases does not require knowledge of exact abundances of vectors and pathogens; rather, a focus is defined by the presence, or some minimal level of abundance, of a vector and pathogen. Stepwise discriminant analysis (DA) was applied to data on free-ranging adult wood ticks (the vector) and to data on isolations of Colorado tick fever virus from small mammals. Trap stations were grouped on the basis of relative abundance of wood ticks for one set of analyses and on the presence or absence of virus for another set of analyses. Additional data consisted of easily measured environmental variables. It is concluded that DA provides a useful tool for analysis of ecosystem structure and an effective means of identifying foci of infection.

Rabies antibody prevalence and virus tissue tropism in wild carnivores in Virginia.

Carnivores trapped in a rabies control program in Virginia were examined for rabies virus and serum neutralizing antibody. Local antibody prevalence ranged from 0% to 29% in gray foxes (Urocyon cinereoargenteus). Rabies virus was pantropic in naturally infected gray foxes and a bobcat (Lynx rufus).

The landscape epidemiology of rabies in Virginia.

Rabies virus, the gray fox, and the Alleghenian Biotic Region form a pathobiocenose; rabies in Virginia exists in a diffuse nidus, the Alleghenian Biotic Region. Physiographic features may serve as barriers or as passageways for epidemic spread of rabies. Epidemic spread is characterized by a radial pattern and a linear northeast-southwest pattern reflecting physiographic features. Incidence of rabies in the fox varies according to seasons. Present control efforts are generally ineffective; under certain conditions, population reduction for control of rabies may be detrimental instead of beneficial.