Production of Borreliacidal Antibody to Outer Surface Protein A In Vitro and Modulation by Interleukin-4

Abstract

Borreliacidal antibody production is one of several parameters for establishing the effectiveness of Borrelia burgdorferi vaccines. The production of borreliacidal antibody was studied in vitro by culturing immune lymph node cells with macrophages and B. burgdorferi. We showed that borreliacidal antibody, directed primarily against outer surface protein A (OspA), was readily produced by lymph node cells obtained from C3H/HeJ mice vaccinated with formalin-inactivated B. burgdorferi in aluminum hydroxide, but not recombinant OspA. AntiOspA borreliacidal antibody was detected in supernatants of cultures of lymph node cells obtained on day 7 after vaccination, peaked on day 17, and rapidly declined. The borreliacidal activity was attributable to immunoglobulin G1 (IgG1), IgG2a, and IgG2b antibodies. When lymph node cells were treated with interleukin-4 (IL-4), production of borreliacidal antibody was inhibited but was unaffected by treatment with anti-IL-4 antibodies. These results suggest that other cytokines, but not IL-4, are mainly responsible for production of the secondary borreliacidal antibody response.Infection with Borrelia burgdorferi, the etiologic agent of Lyme borreliosis, induces a protracted, yet vigorous, humoral immune response (6,8). Most of the anti-B. burgdorferi antibodies involved in this response are important for confirming the clinical diagnosis of Lyme borreliosis (6,8,9), while they play a minor role in protecting the host against infection. Furthermore, several of these anti-B. burgdorferi antibodies, especially those directed against outer surface protein A (OspA), OspB, OspC, and the 39-kDa periplasmic protein, have a unique dual function. These antibodies are highly specific for the serodiagnostic identification of infection with B. burgdorferi, and they can kill B. burgdorferi in the presence of complement (2,20,(24)(25)(26)(27). Induction of borreliacidal antibodies is helpful in evaluating the potential of B. burgdorferi vaccines (5,11,22,29).Recently, clinical trials of two Lyme borreliosis vaccines containing OspA demonstrated that they could protect humans from becoming infected with B. burgdorferi (28, 32). A major concern, however, is the duration of protection afforded by the anti-OspA borreliacidal antibody response. Previously we showed (22) that vaccination with recombinant OspA (rOspA) induced only a short-lived protective borreliacidal antibody response, even after a booster vaccination. Similarly, OspA borreliacidal antibody waned rapidly in hamsters by week 10 of vaccination (22). Thus rOspA or other B. burgdorferi antigens that induce borreliacidal antibodies must be capable of maintaining sustained high levels of borreliacidal antibodies. This would reduce the number of vaccinations required for induction of borreliacidal antibody and lessen the potential for developing adverse side effects that may resemble arthritis (7). Recently, we showed that severe destructive arthritis could be elicited in vaccinated animals challenged with B. burgdorferi only during periods w...

Gamma Interferon Inhibits Production of Anti-OspA Borreliacidal Antibody In Vitro

“…One approach to increase the duration of protection and lessen the potential for adverse effects is to determine the immune mediators responsible for the production and maintenance of borreliacidal antibody. We showed previously (23) that IL-4 does not augment the production of anti-OspA borreliacidal antibody, even though IL-4 is known to up-regulate B-lymphocyte growth and differentiation (27). In fact, IL-4 inhibited the production of anti-OspA borreliacidal antibody, including IgG2a, by lymph node cells obtained from vaccinated mice (23).…”

“…Recently, we developed an in vitro system to determine the effects that immunologic mediators have on the production and regulation of borreliacidal antibody. AntiOspA borreliacidal antibody was readily produced when lymph node cells obtained from vaccinated mice were cultured with macrophages and B. burgdorferi (23). When OspA borreliacidal antibody-producing cells were exposed to a known B-lymphocyte-stimulating factor (27), interleukin 4 (IL-4), borreliacidalantibody production was inhibited.…”

“…It is known that IL-4 strongly down-regulates functions promoted by IFN-␥ (26), especially class switching to immunoglobulin G2a (IgG2a) by B lymphocytes (36). Since B. burgdorferi organisms are killed by IgG2a and complement (23), we sought evidence of whether IFN-␥ augments anti-OspA borreliacidal-antibody production. Such information could provide insight into the mechanism of borreliacidal-antibody production and contribute to the development of a more efficacious Lyme borreliosis vaccine.…”

Interleukin-6 Enhances Production of Anti-OspC Immunoglobulin G2b Borreliacidal Antibody

“…The number of spirochetes on each filter was determined by viewing 20 fields (22). The borreliacidal antibody titer was defined as the reciprocal of the dilution preceding the dilution at which the number of spirochetes was equal to the control.…”

“…Detection of borreliacidal antibody by membrane filtration was performed as described previously (22). Briefly, frozen supernatants were thawed, heat inactivated (56°C for 30 min), sterilized by passage through a 0.2-m-pore-size filter (Acrodisk; Gelman Sciences, Ann Arbor, Mich.), and serially twofold-diluted (1:1 to 1:4,096) with fresh BSK medium.…”