Safety, efficacy, and immunogenicity of a recombinant Osp subunit canine Lyme disease vaccine.

A subunit canine Lyme disease vaccine formulated with recombinant lipidated Osp A and OspB and saponin QS21 was assessed for safety, protective efficacy, and immunogenicity. Ten normal beagles were subcutaneously vaccinated twice at age 12 and 16 weeks, respectively. Three months after the second vaccination, the vaccinates and another 10 nonvaccinated control beagles were challenged by feeding ticks on each dog for 5 days using eight field-collected adult female and six adult male Ixodes scapularis infected with Lyme disease spirochetes per dog. Adverse reactions associated with the vaccinations were limited to injection site swellings which occurred within the first 48 h and resolved within a week. The local reaction was independent of vaccination times and tick challenge. On the basis of typical clinical signs, xenodiagnosis, and diagnostic immunoblotting, all 10 controls were infected; five developed lameness and three of them experienced at least two to three episodes of limping during a 10-month monitoring period. In contrast, eight of ten vaccinates were protected and two infected vaccinates, as judged by xenodiagnosis, were asymptomatic. None of the protected vaccinates developed antibodies to diagnostic spirochetal antigens other than OspA and OspB. In contrast, most controls produced antibodies to borrelial antigens, but not to OspA and OspB. Antibody production in vaccinates receiving a third vaccination 10 months postchallenge was greatly boosted; the geometric mean antibody titer was significantly higher (P < 0.0001) than that tested prechallenge. Thus, the subunit canine Lyme disease vaccine was safe and protective and elicited immunological memory. Vaccinated dogs were serologically distinguishable from those naturally exposed.

In vitro and in vivo evaluation of effects of a heptanoyl tripeptide, FK-565, on porcine macrophage and lymphocyte function.

A series of experiments was performed in vitro and in vivo to determine the influence of FK-565, a heptanoyl tripeptide, on lymphocyte and macrophage function in swine. Compared with values for control cultures, mitogen-stimulated lymphocyte blastogenesis and interleukin-2 production were unaffected in cells preincubated with 0.1, 1.0, and 10.0 micrograms of FK-565/ml. Natural killer cell activity was increased by preincubation with 1.0 microgram of FK-565/ml; however, this increase was not statistically significant. In vitro treatment of porcine alveolar macrophages with FK-565 did not enhance cytolytic activity or bactericidal activity. In in vivo experiments, FK-565 given orally to pigs at concentrations of 6 or 60 micrograms.kg-1.d-1 for 5 days did not affect lymphocyte blastogenesis, interleukin-2 production, or alveolar macrophage bactericidal activity. A trend toward increased natural killer cell activity was evident in pigs treated with FK-565. In contrast, pigs treated with 6 micrograms.kg-1.d-1 had significantly (P less than 0.01) decreased alveolar macrophage cytolytic activity. These data indicate that at the dosages tested, FK-565 is not a suitable immunomodulator for enhancement of nonspecific immunity in swine.

Evaluation of a biological response modifier: effects on starter pig performance.

The influence of a biological response modifier (FK-565) on weanling pig performance was evaluated. One hundred twenty-five weanling pigs (weaned at 21 +/- 3 d) averaging 6.3 kg were utilized in a 35-d growth trial. Dietary treatments included a basal diet (1.25% lysine, corn-soybean meal-dried whey), the basal plus .1, 1 or 10 ppm FK-565 and the control plus an antibacterial combination containing chlortetracycline, sulfamethazine and penicillin. Performance was recorded weekly, and on d 35 all pigs were bled for whole blood and serum chemistry profiles and then were euthanatized. Heart, liver, kidneys and spleen weights were recorded. Also, gross and histological examinations were made of these organs, as well as sections of lung, ileum, bone marrow, thymus and mesenteric lymph node. By d 14, pigs fed the antibacterial diet gained faster (P less than .06) than pigs fed the control and FK-565 diets. However, no differences (P less than .10) in feed intake at d 14 or efficiency of feed utilization at either d 14 or 35 were observed. For the overall 35-d trial, ADG was greater (P less than .01) for pigs consuming the antibacterial diet than for pigs consuming control and the FK-565 diets. Pigs consumed more of the antibacterial diet than of the other diets (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Isolation and characterization of lymphocytes from bovine intestinal epithelium and lamina propria.

The lymphocyte populations of the bovine gut lamina proprial (LP) and epithelial tissues were isolated and characterized with respect to cells bearing surface and cytoplasmic immunoglobulin (Ig). Functional characteristics of cells from the two tissues, including responsiveness to Concanavalin A (Con A), anti-bovine immunoglobulin (anti-Ig), Con A supernatants of bovine peripheral blood lymphocytes (bConA sup) and recombinant human IL-2 (rhIL-2), were also assessed. Less than 1% of the mononuclear cells in the epithelial tissue (IEL) stained for cytoplasmic Ig, and 9% stained positively for surface Ig. IEL did not proliferate in response to anti-Ig, although cells of this population did respond to Con A, bConA sup, and rhIL-2. Twenty-seven percent of bovine gut LP lymphocytes stained for surface Ig, while 39% of these cells were positive for cytoplasmic Ig. LP lymphocytes proliferated in response to all four stimulants used, Con A, anti-Ig, bConA sup and rhIL-2.

Production of anti-sporozoite antibodies in absence of response to carrier by coupling an MDP derivative to a malaria peptide-tetanus toxoid conjugate.

A synthetic peptide (pep) representing a portion of the Plasmodium knowlesi circumsporozoite protein attached to a tetanus toxoid (TT) carrier, has been shown to be immunogenic when delivered in saline with derivatives of the synthetic adjuvant, muramyl dipeptide (MDP). The present study was designed to determine if the degree of substitution of pep and of MDP derivatives on the tetanus toxoid (TT) carrier, as well as the choice of MDP derivative used play a role in determining anti-pep and anti-TT antibody levels. One of the MDP derivatives used in the conjugates was epsilon-amino-caproic Murabutide, since Murabutide which is currently in clinical trials cannot be conjugated. The results show that low doses of this derivative coupled with pep on TT can be used to stimulate high levels of circulating anti-pep antibodies without augmenting the anti-carrier response. In addition, anti-pep antibodies elicited in response to one of the conjugates were biologically active since they produced shedding of the circumsporozoite coat of live parasites.

Biologically active antibodies elicited by a synthetic circumsporozoite peptide of Plasmodium knowlesi administered in saline with a muramyl dipeptide derivative.

A synthetic peptide whose sequence was derived from the circumsporozoite protein of Plasmodium knowlesi coupled to bovine gamma globulin has been shown to be immunogenic when administered with Freund complete adjuvant. The present experiments were designed to test the immunogenicity of the peptide when attached to a tetanus toxoid carrier and administered with alum or murabutide, both acceptable clinical adjuvants. In both cases, the use of an adjuvant increased the levels of circulating anti-peptide antibodies over those observed when no adjuvant was used. However, when the antisera were tested for reactivity with the native protein, animals of the group receiving the conjugate associated with murabutide always had titers greatly exceeding those observed in animals that received the conjugate with alum. Moreover, the sera of the murabutide-treated group were shown to be more active in eliciting shedding of the circumsporozoite protein than were sera of animals of the Freund complete adjuvant-treated group. The use of tetanus toxoid in secondary immunizations could be eliminated when the mice primed with peptide-tetanus toxoid and murabutide were boosted with a polymer of the peptide. The results indicate that the synthetic malarial peptide-tetanus toxoid conjugate is capable of stimulating high levels of biologically active antibodies only when administered with murabutide.

Interrelationship of primed B cells with the potential for IgE and/or IgA expression.

The relationship between the pathways of B cell differentiation leading to IgE or IgA expression was analyzed by assessing the isotype potential of primed B cells as revealed over many generations of clonal outgrowth in splenic fragment cultures. Cells from (CBA/N X BALB/C) F1 male and female mice primed with phosphocholine (PC)-hemocyanin (Hy) and given a secondary stimulus with PC-Hy or PC-determinants via an Ascaris infection gave rise to a large proportion (25-48%) of clones which expressed anti-PC IgE along with any one or mixture of other isotypes, especially IgG and/or IgA. Accompanying the appearance of these cells in the Peyer's patches following Ascaris infection was the steady rise in IgA committed cells over a 12 week period. The potential to express IgE seems to be a normal feature of the development of secondary or memory cells. The coexpression of IgE randomly with all other isotypes supports a linear rather than a branched pathway of B cell differentiation. Ascaris or PC-determinants given to F1 mice were not unique in their ability to prime cells with the potential for IgE expression. Stimulation of BALB/c mice with two low doses of N-acetyl-glucosamine-conjugated hemocyanin (GlcNAc-Hy) primed cells in vivo generated a high proportion (63%) of clones in vitro that expressed IgE and most of these exclusively coexpressed IgA (16/26) suggesting a progressive restriction in isotype potential. Cells which gave rise to IgE producing clones specific for the priming hapten did not support the expression of IgE by clones of other specificities costimulated in vitro (anti-inulin, anti-beta-galactosyl). Thus the potential to express IgE seems to be both an inherent property of the B cells and under hapten-specific or hapten-linked regulation.

Morphology and reproductive organs and oogenesis in bisexual and unisexual transplants of mature Schistosoma mansoni females.

Mature, egg-producing female worms from bisexual cercarial infections in mice were transplanted surgically either without male worms, to produce unisexual infections in recipient hamsters, or with male partners to produce bisexual infections. The morphology of the female reproductive organs and oogenesis in the unisexually and bisexually transplanted females were compared over a 9-day period. Females which paired with male worms in hamsters continued to produce eggs throughout the experiment. In contrast, unisexually transplanted females exhibited degeneration of the vitellaria at 3 days and the ovary at 6 days posttransplantation, although these worms produced fertilized oocytes as late as 9 days following transfer. Female worms which had degenerated upon separation from male worms for 3 mo regenerated and produced viable eggs when reunited with mature males. Thus, separation of females from their male partners leads to a reversible degeneration of the female reproductive tract.