Predisposing factors for individuals' Lyme disease prevention practices: Connecticut, Maine, and Montana.

OBJECTIVES: This study examined factors that predispose individuals to protect against Lyme disease. METHODS: Knowledge, attitude, and practice questions concerning Lyme disease prevention were included in the Behavioral Risk Factor Surveillance surveys in Connecticut, Maine, and Montana. A total of 4246 persons were interviewed. RESULTS: Perceived risk of acquiring Lyme disease, knowing anyone with Lyme disease, knowledge about Lyme disease, and believing Lyme disease to be a common problem were significantly associated with prevention practices. CONCLUSIONS: Predisposing factors differ substantially between states and appear related to disease incidence. Personal risk, knowing someone with Lyme disease, and cognizance about Lyme disease and acting on this information are consistent with social learning theories.

Evaluation of viral-lysate enzyme-linked immunosorbent assay kits for detecting human immunodeficiency virus (type 1) infections using human sera standardized by quantitative western blotting.

The first generation of proprietary reagents for detecting antibodies to the Human Immunodeficiency Virus Type 1 (HIV-1) by enzyme-linked immunosorbent assay (ELISA) used as antigen partially purified virus from cell culture lysates. These tests, which are still in use, may vary in their antibody measurement capabilities if different proportions of the viral polypeptides are present in the viral lysate mixtures. We determined the quantities of antibodies in the serum of persons infected with HIV-1 by dilution analysis using 3 ELISA kits: Abbott [A], Du Pont [D], Genetic Systems [G]. The proportionate antibody titres of each serum to p24gag and gp160env/120env were established by quantitative Western blotting. Serum antibody titres were high, frequently over 1:10,000, a result observed both by ELISA and Western blot. For Kit D, sera with high proportions of antibody to p24gag produced antibody titration curves with steep slopes whereas shallower slopes were found in sera with high proportions of antibody to gp160env. In contrast, Kit A gave steeper slopes with sera enriched for gp160env antibodies. Kit G gave results with slopes intermediate between Kits A and D. Serum antibody titres differed between kits depending upon the proportion and concentration of antibodies in a given serum to gp160env and p24gag. The findings that both the concentration and proportion of antibodies to specific viral polypeptides in human sera markedly affect the signal intensity produced by proprietary ELISAs suggest the need for several control sera which reflect the diversity of human serum responses. Standardization of human reference sera by quantitative Western blotting will assist in evaluation and quality control of ELISA tests.

Quantitation of antibody reactivity to human immunodeficiency virus (type 1) proteins and glycoproteins on Western immunoblots by reflectance densitometry.

The human serum antibody response to polypeptides of human immunodeficiency virus type 1 (HIV-1) was quantitated by reflectance densitometry of Western immunoblots by using two commercially available blotting systems. In one system, human antibodies were detected by an avidin-biotin method using peroxidase as the label, and in the other, human antibodies were detected by peroxidase-labeled conjugate against human immunoglobulins. When staining intensity was plotted against the log of the serum dilution, a shallow slope was evident, with a 50% change in staining intensity requiring as much as a 100-fold change in antibody content. The linear range of the staining intensity curves was frequently found in serum dilutions of 1:2,500 to 1:1,000,000, and a plateau was often observed at high antibody concentrations (1:80 to 1:640). When replicate strips were tested, staining intensities varied by +/- 7 to 37%. Antibodies to p24gag and gp160env were readily detectable in several sera diluted 1:1,000,000, a result seen with both blotting systems. If Western blotting were to be used to observe increase or decreases in levels of antibodies to various polypeptides, several widely spaced serum dilutions would need to be tested.

Injection of inactivated phase I Coxiella burnetii increases non-specific resistance to infection and stimulates lymphokine production in mice.

The encounter of phase I C. burnetii with the host results in seemingly disparate consequences. On the one hand, in vitro lymphocyte responses to mitogens and homologous recall antigen are suppressed. On the other, host resistance to a variety of infectious agents and to a tumor is increased. An explanation for this augmented immune response surely involves the ability of C. burnetii to stimulate cytokines, such as interferon and TNF, which enhance host immune function.

Characterization of a phase I Coxiella burnetii chloroform-methanol residue vaccine that induces active immunity against Q fever in C57BL/10 ScN mice.

The effect of phase I Coxiella burnetii chloroform-methanol residue vaccine (CMRV) on the response of murine splenic lymphocytes to mitogenic and antigenic stimuli was evaluated in C57BL/10 ScN endotoxinnonresponder mice with an in vitro lymphocyte proliferation assay. Intraperitoneal injection of phase I CMRV resulted in antibody production against phases I and II antigens. Lymphocytes were responsive in vitro to concanavalin A, phytohemagglutinin, pokeweed mitogen, and specific recall antigens. Antibodies against phases I and II antigens were not detected after intraperitoneal injection of chloroform-methanol extract (CME). Lymphocytes also were only slightly hyporesponsive to mitogens. Reconstitution of the CMRV with the CME of phase I whole cells restored the immunopathological reactions that were associated with the phase I whole cell vaccine (WCV). The CMRV was more mitogenic than the WCV for lymphocytes from mice injected with saline. Lymphocytes from phase I WCV-injected mice were negatively modulated with nontoxic concentrations of homologous WCV or CMRV. Lymphocytes from phase I CMRV-injected mice were only slightly hyporesponsive to mitogens and were significantly stimulated by antigens of either WCV or CMRV as recall antigens. Vaccination of mice with 100 micrograms of CMRV, CME, or WCV provided 80, 0, or 50% protection, respectively, against a lethal intraperitoneal challenge with viable phase I C. burnetii. The epitopes which induce immunological hyporesponsiveness, negative modulation, and the death of lymphocytes were fractionated into the CMRV and CME. The CMRV provides at least one of the determinants which induce immunosuppression, whereas CME contains specific or nonspecific components or both. Collectively, these results show that the CMRV may be a potential candidate to replace the WCV currently used for human vaccination.

Suppression of in vitro lymphocyte proliferation in C57BL/10 ScN mice vaccinated with phase I Coxiella burnetii.

The effect of inactivated phase I and phase II Coxiella burnetii whole cell vaccine (WCV) on the response of murine spleen cells to mitogenic and antigenic stimuli was evaluated in C57BL/10 ScN endotoxin nonresponder mice with an in vitro lymphocyte proliferation assay. Intraperitoneal injection of phase I WCV into mice resulted in marked and persistent suppression of the proliferative response of spleen cells to concanavalin A, phytohemagglutinin, and pokeweed mitogen. This response was time and dose dependent and was not associated with decreased lymphocyte viability. By using a standard dose of 100 micrograms of phase I WCV, suppression of mitogenic responsiveness was first detected 3 days postinjection, attained maximum levels by day 14, and persisted for longer than 5 weeks. Suppression of mitogenic lymphocyte proliferation also was demonstrated after inoculation of animals with viable phase I organisms. The observed hyporesponsiveness of spleen cells from phase I WCV-injected animals was not either the result of a shift in the mitogenic dose optimum or due to a change in the day of in vitro peak response. Spleen cells from phase I WCV-injected mice were negatively regulated with homologous antigen. Investigation of the mechanism of action of phase I WCV, with a 51Cr-release assay, and trypan blue dye exclusion showed that phase I WCV was not directly cytolytic or cytotoxic to spleen cells from normal or vaccinated mice. Phase II WCV did not induce significant mitogenic hyporesponsiveness or negative modulation of spleen cells. These findings extend the observations of adverse host responses associated with the phase I WCV and underscore the need to develop a microbial fraction which possesses protective potency but which lacks the propensity to induce deleterious tissue reactions and immunosuppression.