Isolation and characterization of rabbit caecal pectinolytic bacteria.

Two hundred and thirty colonies from the caecal contents of six rabbits were picked up and, after a 2-d incubation, were microscopically characterized using Gram staining. Large Gram-negative (34%) and small Gram-negative (30%) irregular rods, Gram-negative (27%) and Gram-positive (8%) cocci were found. Eleven isolates (Bacteroides ovatus (6 strains), B. thetaiotamicron, B. caccae, B. stercoris, B. capillosus and Capnocytophaga ochracea) were identified using commercial tests for measuring their catalase activity, metabolite production, etc., and testing their growth in 20% bile. Bacteria belonging to the genus Bacteroides were demonstrated to be the principal pectinolytic organisms in the rabbit caecum.

Biochemical characteristics and fermentation of glucose and starch by rabbit caecal strains of Bifidobacterium globosum.

Two strains of Bifidobacterium globosum were isolated from caecal contents of rabbits in a search for potential probiotics. Both strains fermented glucose, galactose, pentoses, maltose, raffinose and starch. Common coccidiostats (monensin, salinomycin) and antimicrobial growth promotors (avoparcin, bacitracin, nitrovin, virginiamycin) supplied at 10 mg/L inhibited their growth in cultures with glucose. Fermentation parameters of bifidobacteria on glucose and starch differed. More formate and ethanol and less lactate were produced during growth on glucose than during growth on starch. When growing on starch, the two strains of bifidobacteria produced 1 mol lactate per 5.6 and 5.7 mol acetate, respectively. Corresponding values during growth on glucose were 17.3 and 8.4 mol of acetate per mol of lactate. Starch-grown cells accumulated more saccharides than cells grown on glucose (1.48 vs. 0.41 and 3.12 vs. 1.18 mmol glucose units per 1 g of dry matter, respectively).

[Immunology of the mammary gland of cattle]. / Immunologie der Milchdrüse beim Rind.

A successful control of udder diseases in dairy cattle widely depends on the knowledge of the mammary gland immune functions. They are responsible not only for the self-protection of this organ but also for the supply of the newborn with immunoprotective substances of humoral and cellular character. In the mammary gland, selected immunology methods may be used in the diagnosis of both local and systemic function disorders. Such evaluation represents a necessary prerequisite for a possible treatment by immunomodulators.

[Adjuvant effects of glucan on antibody formation in swine]. / Adjuvante Wirkung von Glukan auf die Antikörperbildung beim Schwein.

The effect of glucan, a yeast product isolated from Saccharomyces cerevisiae, on the antibody production to the bovine serum albumin and tetanus toxoid was investigated in miniature pigs. A significant stimulation of the immune response to both antigens differing in their thymus dependency was demonstrated during three weeks after the glucan application, by ELISA, in comparison to the untreated controls.

Assessment of lymphocyte and phagocytic functions in goats treated with glucan.

The effect of glucan, a biological response modifier of yeast origin, on different immune functions was studied after the intramuscular application in goats. The simultaneous administration of glucan with human serum albumin or tetanus toxoid significantly stimulated the antibody production to both antigens differing in their thymus dependency. Similarly, the phagocytizing activity of the blood polymorphonuclear leukocytes measured by the reductase colorimetric assay significantly increased one week after the glucan treatment. However, suppression of T-lymphocyte function in experimental animals was determined by the lymphocyte transformation test particularly in response to phytohemagglutinin and concanavalin A. The results of the study indicate that glucan can modulate some elements of the ruminant immune response.

[Determination of antibodies to Streptococcus agalactiae in the milk of dairy cows using the ELISA test]. / Stanovení protilátek proti zárodkum Streptococcus agalactiae v mléku dojnic testem ELISA.

A sensitive 4-layers ELISA test for determination of antibodies against the pathogens of Streptococcus agalactiae in cows' milk was used for diagnosis of mastitis, with the aim to broaden these methods. Antigen was linked on the solid phase in the form of the whole bacteria, and milk was tested, diluted in the ratio of 1:10. Antigen bound-specific antibodies were labelled with pig antibodies against bovine immunoglobulins and in the next layer with rabbit antibody conjugated with peroxidases against pig immunoglobulins. After test visualisation and reading on the photometre, the results were given in the positivity per cent as a 100-multiple of the proportion of absorbance of the unknown sample and the positive control after subtraction of the negative control. Milk was examined in 36 dairy cows from three various breeding herds by that method. The samples were parallelly examined bacteriologically and cytologically. In the milk of dairy cows with positive S. agalactiae finding, the main level of antibodies expressed a positivity per cent, was 15.0%, while in bacteriologically negative animals it was only 6.2%. The dairy cows were divided into 8 groups, characterizing various stages of mastitis, according to the results of the individual treatments.

Concomitant immunity leads to retardation or acceleration of the growth of Rous sarcomas in genetically resistant or susceptible inbred lines of chickens.

We report results on the age-dependent effect of the B (MHC) genotype on resistance to the growth of a second RSV tumour in chickens from highly inbred lines genetically resistant or susceptible to progressive growth of primary RSV-induced tumours. Furthermore, the second inoculation of RSV caused either accelerated or retarded growth of the primary tumours induced by the same virus. These two types of response to a second challenge with RSV were controlled by alleles of the chicken major histocompatibility (B) complex. The retarded growth of the primary tumours was found to be thymus-dependent. Furthermore, a clear-cut trans-complementation effect of two B alleles on the response to RSV challenge was demonstrated.

An enzyme-linked immunosorbent assay for detecting the chicken B cells.

Two modifications of an indirect enzyme immunoassay described here allow the discernment of chicken B and T cells when a polyclonal rabbit anti-chicken Ig antibody or a monoclonal antibody reactive with chicken IgM and IgG heavy chains is used. Comparison of both types of antibody in ELISA and in indirect immunofluorescence suggests that they can readily be exploited for detection of lymphoid cells with surface immunoglobulin markers.

Different importance of primary lymphoid organs for Rous sarcoma regression in inbred lines of chickens.

Resistance to progressive growth of tumours induced by Rous sarcoma virus is controlled mainly by genes linked to the B complex (the major histocompatibility complex) of the chicken. The effect of thymectomy and bursectomy on this resistance was studied in chickens from highly inbred lines and their F1 hybrids which differ by the genotype at the B complex and by the degree of genetically controlled resistance or susceptibility. The results show that thymectomy has considerable effect on growth of RSV-induced tumours in the CB line genetically resistant to progressive Rous sarcoma growth and little effect in (CB X IC)F1 (also genetically resistant) and (CC X IC)F1 (intermediate responders to RSV) hybrid chickens. Bursectomy influences the expression of this resistance to a lesser extent than thymectomy. The results indicate that resistance to the development of progressively growing tumours is of a complex nature, the individual components of the immune system are more or less important for its expression in different experimental models. Thus genetically defined animal models have become useful tools for studying carcinogenesis.

Resistance to Marek's disease is controlled by a gene within the B-F region of the chicken major histocompatibility complex in Rous sarcoma regressor or progressor inbred lines of chickens.

Rous sarcoma "regressor" chicken lines CB and CB.R1 identical in the B-F region of the B complex (MHC) are susceptible to Marek's disease. On the contrary, the Rous sarcoma "progressor" line CC different in the B-F region from the CB and CB.R1 lines and identical in the B-G region with the CB.R1 line is considerably resistant to MD. The inbred chicken line M is susceptible to MD, although it carries the B21 allele which is generally considered to determine MD resistance. Analysis by means of sera specific for B-F and B-G antigens revealed that the B haplotype of the M line is composed of the B-G region coding for the typical B-G21 antigen and of a different B-F region coding for B-Fx antigen of thus far unknown specificity. Thus genetic resistance to MD is controlled by a gene located within the B-F region of the chicken MHC.

A rapid detection of avian oncovirus group-specific antigens in feather pulp by the enzyme-linked immunosorbent assay.

An ELISA procedure for the detection of avian sarcoma-leukosis gs antigen in feather pulp of adult birds is described. The test can be used for identifying gs+ and gs- chickens in leukosis-free populations. The titres of exogenous and endogenous virus-coded gs antigens overlap and the ELISA can be used only for a preliminary screening of unknown chicken populations.

Inhibitory activity of cytosine arabinoside on Marek's disease virus.

The presence of ara-C in growth medium at concentrations of 10(-4) to 10(-7) M completely or partially suppressed the formation of plaques specific for MDV or HVT and decreased proportionally the growth of HPRS line 1 lymphoblastoid cells. Administration of ara-C to chickens immediately after infection with MDV (1 mg/chicken/day i.p. for 5 days) reduced the incidence of Marek's disease by 50%. Thus ara-C appears to be an inhibitor of Marek's disease.

Location of the gene responsible for Rous sarcoma regression in the B-F region of the B complex (MHC) of the chicken.

We studied the fate of tumours induced by PR-RSV-C and B77-C in inbred chicken lines CB, CC and CB.R1. Rous sarcomas regressed in the CB and CB.R1 lines which are identical in the B-F region of the B complex. In contrast, progressive tumour growth was observed in the CC line which differed in the B-F region from the CB and CB.R1 lines and was identical in the B-G region with the CB.R1 line. These results suggest that the gene responsible for Rous sarcoma regression is located in the B-F region of the B complex.

The latex particle adherence assay: inhibitory effects of protein preparations.

The latex particle adherence to peripheral chicken lymphocytes in the presence of different concentrations of various protein preparations was examined. Non-specific inhibition of adherence was observed at and above concentrations of 500 microgram/ml, whereas protein concentrations at and below 250 microgram/ml gave no significant adherence inhibition in control chicken lymphocytes. The protein concentration of 250 microgram/ml of antigens prepared from MDV-infected chicken skin and HPRS-1 cells specifically inhibited the LPA to lymphocytes of MDV-infected chickens.

Increased agglutinability and haemadsorption of Marek's disease HPRS line 1 lymphoblastoic cells after concanavalin A treatment.

The HPRS line 1 lymphoblastoid cells derived from an ovarian lymphoma induced by Marek's disease virus in chickens displayed increased agglutinability and haemadsorption when incubated with Con A. The increase was proportional to the concentration of Con A used. The same Con A-untreated cells and normal chicken lymphocytes incubated with Con A exhibited no increase in agglutinability and haemadsorption, however.

Disinfection of Marek's disease virus in poultry dust.

Dust samples from farms contaminated with Marek's disease virus (MDV) were exposed to various disinfectants under experimental and field conditions. After the disinfection treatment, examination was made for the presence and oncogenicity of surviving MDV by the inoculation of tissue cultures and susceptible chickens. A combination of formaldehyde vapour and a preparation based on iodine bound to organic carriers appeared to be the most effective for disinfection.

[Testing of the protective effect of cell-free lyophilized vaccine against Marek's disease in field trials]. / Overení úcinnosti lyofilizované bezbunecné vakcíny proti Markove nemoci v terénních podmínkách

The protective effect of a lyophilized vaccine against Marek's disease ("Keramvac"--Pfizer), prepared from a cell-free turkey's herpesvirus (strain FC 126), was compared in field trials with losses in the group of non-vaccinated chickens. Under the indicated conditions, the vaccine had only a 50.86% effectiveness. The possible causes of the reduced vaccination effect are discussed with regard to the pathomorphological and virological findings suggesting, among others, an increased incidence of the symptoms of the classical form of Marek's disease in the population investigated.