Persistent Titers Research Articles

Comparison of alum-absorbed or non-alum-absorbed oil emulsion vaccines containing either pilate or non-pilate Bacteroides nodosus cells in inducing and maintaining resistance of sheep to experimental foot rot

Highly pilate (P) or non-pilate (NP) cells of Bacteroides nodosus were compounded into oil emulsion (O) either with or without prior absorption onto alum (A). The abilities of these four preparations (referred to as PAO, NPAO, PO and NPO vaccines) to stimulate antibody production and to protect sheep from foot rot were compared. Two injections of PAO vaccine protected sheep against homologous challenge 12 weeks after the second dose by PO, NPO and NPAO vaccines were less effective. Sheep were protected against homologous challenge for 14 weeks after a single dose of PAO vaccine and for 22 weeks after three doses; an ameliorative effect was still evident 40 weeks after the third dose. Protection against challenge with two heterologous strains was demonstrated at six weeks after three doses of vaccine. A numerical system of scoring the lesions also confirmed that foot rot in vaccinated sheep challenged outside the 'protective' period of the vaccine was somewhat less severe than in controls. PAO vaccine induced much higher and more persistent titres of agglutinins than the other vaccines tested. There was a relationship between agglutinin titres and resistance to homologous challenge.

Adoptive transfer of "persistent' IgE responses in mice in the absence of secondary antigenic stimulation.

Spleen cells were prepared from Balb/c mice immunized 30 days previously with alum-precipitated ovalbumin (OA), which manifested high, persistent titres of anti-OA IgE and IgG. The adoptive transfer of 5.0 X 10(7) such cells to X-irradiated syngeneic recipients produced comparable persistent IgE/IgG responses, in the absence of secondary antigenic challenge. Fractionation procedures indicated that the nylon-wool adherent population from the spleen was the most active in effecting transfer of the response. However, donor T-cells were also required, as pretreatment of the cellular inoculum with anti-Thy 1.2 antiserum ablated transfer. The inclusion of serum containing anti-OA IgG (but not IgE) in the cellular inoculum also blocked the transfer.

Serological responses of sheep and cattle exposed to natural Toxoplasma infection.

During a four and a half year period a group of cattle was grazed continuously with a group of sheep and observed for Toxoplasma antibodies. Initially, there were 25 cattle and 31 sheep, but these were reduced to 19 and 18, respectively, by the end of the observation. Only transient antibody responses were noted in 2 cattle, whereas persistent titres developed in 12 sheep. Interpreted in the light of available information, these results were taken to indicate that cattle do not readily acquire persistent T. gondii infections.

Allergenicity of Concanavalin A in Mice

Concanavalin A (Con A) is a potent allergen in certain strains of mice and in particularly the H-2Kk mice, A/J, CBA/H, and C3H/He. Using a dose of 100 microgram, the subcutaneous route of injection was the most effective means of inducing high, persistent titers of T cell-dependent circulating anti-Con A reagins without the addition of the classical IgE adjuvants, aluminium hydroxide and Bordetella pertussis vaccine. Haptenated Con A induced reagins with antihapten specificity. In the discussion, one possible contributing factor in Con A allergenicity in genetically responder strains of mice is emphasised, namely, persistence in subcutaneous injection sites.

Protective effects of colostral antibodies to Br abortus on strain 19 vaccination and field injection.

Calves which have received no antibodies against Br abortus in their colostrum may respond to strain 19 vaccination even on the first day of life. However, calves with such antibodies may completely suppress any response to S19 vaccination. In calves which have received very high titres of passive antibodies from their dams complete suppresson of vaccinal response may be expected to occur up to about 153 days of age. Thus, if vaccination is restricted to between 90 and 180 days many calves in infected herds will not be protected by routine vaccination with S19. In calves born of and reared on infected dams the colostral antibodies also have a marked protective effect. In spite of heavy exposure to Br abortus at birth and later from infected milk only six out of 64 calves (9.4 per cent) developed persistent positive titres. The remaining calves reverted to zero titres within 12 months and an anamnestic test indicated that of these up to 15 per cent may have been latent carriers but even more remarkably, 85 per cent of such calves were not even "primed" by such heavy exposure.

Incidence and Significance of Islet-cell Autoantibodies in Different Types of Diabetes Mellitus

Islet-cell (ICA) and organ-specific autoantibodies (OSA) were determined by the indirect immunofluorescence technique in 920 diabetics, 1,159 nondiabetic patients, and 100 young and 100 adult healthy controls with normal glucose tolerance. In control subjects ICA were not detected, and only 20 miscellaneous patients with normal glucose tolerance showed ICA (1.7 per cent). ICA were present in 45.4 per cent of patients with juvenile insulin-dependent diabetes (IDD) during the first six months of disease and in 29.1 per cent of patients between 6 and 12 months of disease onset; ICA presence decreased to 19.2 per cent and 20.6 per cent after one and five years of duration of diabetes. In patients with maturity-onset IDD, ICA incidence was 19.4 per cent in the first year, 20 per cent between one and five years, and 12.2 per cent after five years of disease. In this group, 64 per cent of ICA-positive patients showed clinical and/or serologie evidence of thyroid, gastric, or adrenal autoimmune disorders. In sera from young patients with non-insulin-dependent diabetes (J-NIDD), ICA were not detected. In adult patients with the same type of diabetes (M-NIDD) ICA incidence was 9.8, 7, and 8.9 per cent and was not related to the duration of diabetes. Patients with chemical diabetes were divided into two groups (younger and older than 35 years), and ICA incidence was 18.9 and 12.9 per cent, respectively. In two nondiabetic patients, glucagon cell autoantibodies were detected. ICA titers were variable in juvenile IDD of recent onset. Persistent ICA titers, frequently associated with OSA, were observed in the other types of diabetes, with the exception of J-NIDD. ICA may be considered markers of severe beta-cell alteration, with consequent reduction of insulin secretion, even though insulin dependency is sometimes delayed in a few patients.

Feline Leukemia Virus Infection: Age-Related Variation in Response of Cats to Experimental Infection2

Sixty-seven specific-pathogen-free cats of various ages (newborn, 2 wk, 1 mo, 2 mo, 4 mo, and 1 yr) were inoculated ip with either the Rickard (R) or the Kawakami-Theilen (KT) strain of feline leukemia virus (FeLV). Susceptibility to FeLV was judged by induction of a) FeLV group-specific antigens (gsa) in leukocytes, b) FeLV-related disease, c) antibody to feline oncornavirus-associated cell membrane antigen (FOCMA), and d) virus-neutralizing (VN) antibody. Susceptibility to FeLV-decreased with age. Persistent viremia and FeLV-related disease developed in 100% of cats inoculated as newborns, in 85% of cats inoculated at 2 weeks to 2 months of age, and in 15% of cats inoculated at 4 months or 1 year of age. Cats susceptible to FeLV leukemogenesis became persistently FeLV gsa-positive (viremic) at 4 weeks post inoculation and thereafter and produced little or no FOCMA or VN antibody. Cats that resisted leukemogenesis by FeLV all developed persistent FOCMA and VN titers and never became FeLV gsa-positive. The disease in inoculated cats was influenced by virus strain; FeLV-R induced predominantly thymic lymphosarcoma, whereas FeLV-KT caused fatal nonregenerative anemia without concurrent neoplasia.

Effects of antilymphocyte serum and splenectomy on resistance to Babesia microti infection in hamsters

Since the immune mechanisms active in response to babesiosis have not been clearly defined, the effects of antilymphocyte serum (ALS) and splenectomy on B. microti infections were assessed in immune and susceptible hamsters by degree of parasitemia, clinical course, and humoral antibody formation. In immune animals treated with ALS or splenectomy, latent infections became patent, but parasitemias during exacerbation peaked at lower levels than was the case with primary parasitemias. However, despite similar parasitemias and equivalent humoral antibody induction in both groups, seven of nine ALS-treated animals died, whereas only one of seven splenectomized hamsters died. All hamsters treated with ALS before and during primary infection died with persistent peak parasitemias and low serum titers against B. microti. Animals subjected to splenectomy before initial inoculation had an essentially normal clinical course for B. microti infection except that low levels of parasitemia persisted for many weeks and two of eight died. Splenectomized hamsters had normal humoral responses. Although cellular responses are mainly responsible for protection in babesiosis, humoral antibodies may alter the course of this disease. In view of the rather ubiquitous occurrence of Babesia spp. organisms in wild and domestic animals, this parasitosis may be more common in humans than is presently recognized, especially in immunosuppressed or splenectomized individuals and in persons with otherwise reduced cellular immune responses.

Prognostic Factors in Cryptococcal Meningitis

Results of amphotericin B therapy were correlated with laboratory and clinical findings in 111 patients with cryptococcal meningitis. Compared with patients who were to be cured, patients who were to die during therapy more often had the following features on admission: lymphoreticular malignancy or corticosteroid therapy; cerebrospinal fluid with high opening pressure, a low glucose level, less than 20 leukocytes/mm3 and cryptococci seen in smear; cryptococci isolated from extraneural sites; and high titers of cryptococcal antigen in cerebrospinal fluid and serum. These last two features also characterized admission findings in the group of patients who were to be discharged with negative cultures after therapy but who later relapsed. Patients who were to relapse also had high, persistent posttreatment titers of cryptococcal antigen in serum or cerebrospinal fluid.

Antibody production in the plaice ( Pleuronectes platessa L.) after oral and parenteral immunization with Vibrio anguillarum antigens

A study was undertaken of the immune response of 2-year old plaice, maintained in the aquarium at temperatures between 10° and 15°C, to the administration of a heat-killed, sonicated, freeze-dried Vibrio anguillarum vaccine. This was given as a single injection, in saline (6 mg dry weight of bacteria), suspended in Freund's complete adjuvant (4.5 mg dry weight of bacteria), or fed as 1 mg dry weight of bacteria per gram wet weight of diet. Humoral antibody production, both in blood and mucous secretions of the intestine and skin, was measured one year after injection or after a year of daily feeding with the vaccine. Antibody to Vibrio antigens was detectable in higher titres in the intestinal extract from orally immunized plaice, than in their sera. Parenteral immunization with adjuvant resulted in high and persistent antibody titres in the serum, while only small amounts of antibody were found in the intestinal and cutaneous secretions. No circulating antibodies were detectable one year after injection with bacteria in saline. Gel filtration of serum and mucus showed the antibody activity to be associated with a high molecular weight fraction. The production of antibodies in the plaice is discussed, together with the possible efficacy of oral immunization in the prophylaxis of vibriosis.

Nasal immunization of asthmatic children with killed influenza virus

The safety and effectiveness of killed influenza vaccine (Hong Kong strain) given intranasally was studied in 12 children with severe chronic asthma. All responded by producing serum and nasal fluid hemagglutination-inhibiting (HAI) and neutralizing antibodies. Higher serum titers resulted when one dose of intranasal vaccine was preceded by a subcutaneous dose, but two intranasal vaccinations separated by 2 weeks were followed by somewhat more persistent nasal titers. The bulk of antibody activity in nasal fluids was associated with exocrine immunoglobulin A (γA), as has been found in nonasthmatic subjects. When this 11S antibody was converted to 7S γA monomers by reduction and alkylation, its antibody activities were decreased. No adverse effects of intranasal immunization were found. In children with asthma, two spaced courses of intranasal influenza vaccination therefore appear to be safe and to lead to a consistent antibody response. Giving one vaccine dose subcutaneously does not appear to offer any advantage in production of nasal antibody over two intranasal courses.

Application of Research to Bovine Brucellosis Control and Eradication Programs

Recent research on brucellosis has resulted in new developments in the broad areas of immunity, diagnosis, and Brucella characterization. Application of these developments is necessary to continue the progress of the control program toward the goal of eventual eradication of bovine brucellosis.Heifer calves vaccinated at three, four, or six months of age with Strain 19 developed an immunity against brucellosis equal to that in heifers vaccinated at eight months or older. Calves vaccinated at two months also developed a serviceable immunity. Application of vaccination at younger ages will practically eliminate persistent vaccinal titers that have caused some inaccuracies in interpretation of standard diagnostic tests.Specificity of several diagnostic tests has been increased considerably, thus increasing our ability to identify the infected animals. Most of these have been used to supplement the seroagglutination tests in problem herds. The card test is being evaluated further by applying it routinely in states that have not attained a modified certified status.Addition of Brucella phage and oxidative metabolic tests to the biochemic and serologic tests will enhance our capabilities of characterizing Brucella responsible for new outbreaks of brucellosis and our ability to contain such outbreaks.

Q Fever Antibody Response in Experimentally Infected Wild Rodents and Laboratory Animals

Summary Capillary tube agglutination antibody and Phase I and Phase II complement fixation antibody to Coxiella burnetii was studied in five species of experimentally infected wild rodents, and in guinea pigs and white mice. Phase II CF antibody was produced 1 to 2 weeks following i.p. infection of the California AD strain of C. burnetii in all species of animal tested. Peak titers were reached 3 to 5 weeks after infection. Phase I CF and CT agglutination antibody was first demonstrated at 3 to 5 weeks, increasing to peak titers at periods of time varying from 6 to 36 weeks after infection, depending upon the animal species. Phase II CF titers were higher in all animals than Phase I CF or CT agglutinating antibody titers. Persistence of titers was followed for 36 or 52 weeks, depending upon animal type. Ord kangaroo rats produced little demonstrable Phase I CF or CT agglutination antibody. All species of wild rodents injected with formalin-inactivated AD strain of C. burnetii produced low titers of Phase II CF antibody in studies through 16 weeks after inoculation. Phase I CF antibody was barely demonstrable in desert wood rats, Ord kangaroo rats, and pinyon mice. No detectable CT agglutination antibody was formed. No antibody could be demonstrated in five species of wild rodents 28 days after injection with normal egg yolk sac material.

Immunization againstLeptospira pomona

Abstract Extract Leptospirosis is now recognized as a highly invasive, virulent, and often fatal disease of young animals, particularly calves, in which it follows a characteristic course with clinical symptoms of sudden fever accompanied by icterus and haemoglobinuria, with consequential anaemia, and a high mortality. Recovered animals are highly resistant to reinfection, and their blood usually shows a high and persistent agglutination-lysis titre against the appropriate leptospira strain. Another important feature from the epidemiological point of view is the fact that most clinically recovered animals pass through a more or less prolonged carrier phase during which the kidney tubules become colonized by the organisms which are excreted in the urine in enormous numbers and in viable form.