Differential effect of Bacillus firmus on immune response and enterocyte brush-border enzyme levels in BALB/c and B10.BR mice

A nonpathogenic bacterium of external environment possessing remarkable immunomodulatory activity, Bacillus firmus (BF) inactivated with formaldehyde, was given intragastrically to two genetically different mouse strains BALB/c (H-2d) and B10.BR/SnPh (B10.BR, H-2k) reared in conventional (CV) and B10.BR strain also in germ-free (GF) conditions. Repeated intragastric administration of BF (500 micrograms every other day over two weeks, starting at the age of 3 months) significantly enhanced intestinal IgA levels in CV BALB/c mice but did not affect intestinal IgA in CV B10.BR mice. In GF B10.BR mice, IgG levels in sera and intestinal washings increased after BF administration compared to CV B10.BR mice. In CV BALB/c mice, specific activity of enterocyte brush-border enzymes (lactase, gamma-glutamyltransferase, alkaline phosphatase) decreased after BF treatment; sucrase (sucrose alpha-glucosidase) activity was not affected. On the other hand, in B10.BR mice, specific activity of gamma-glutamyltransferase and dipeptidyl peptidase IV were higher after administration of BF in both CV and GF groups relative to untreated controls. The activities of lactase and glucoamylase (glucan 1,4-alpha-glucosidase) were significantly stimulated only in the group of GF B10.BR mice treated with formolized BF. The stimulation of immunoglobulin production after BF treatment was accompanied by changes in the levels of enterocyte brush-border enzymes; this responsiveness to BF treatment was genetically regulated.

Enhanced systemic and mucosal antibody responses to a model protein antigen after intranasal and intratracheal immunisation using Bacillus firmus as an adjuvant

Bacillus firmus, a non-pathogenic Gram positive (G+) bacterium of the external environment was investigated for immunomodulatory properties. It stimulated an increase in anti-ovalbumin IgG in sera, bronchoalveolar lavages and intestinal washings after both intranasal (i.n.) and intratracheal (i.t.) immunisation, and enhanced anti-ovalbumin IgA in intestinal secretions and in bronchoalveolar lavage fluid after i.n. or i.t. immunisation, respectively. The immunomodulatory effect of B. firmus on antibody formation was antigen specific.

Electric manipulation of bioparticles and macromolecules on microfabricated electrodes

Bioparticle separation, bioparticle enrichment, and electric field-mediated immune detection were carried out on microfabricated semiconductor chips utilizing ac and dc electric fields. Microscale separation on a chip surface having an active area of approximately 16 mm2 was demonstrated for a mixture of Bacillus globigii spores and Escherichia coli bacteria. Dielectrophoretic enrichment was performed by collecting target bioparticles from a flow stream in flow cells of 47.5 microL, achieving a 20-fold increase in the concentration of E. coli bacteria from a diluted sample, a 28-fold enrichment for peripheral blood mononuclear cells from red blood cells, and a 30-fold increase in white blood cells from diluted whole blood. The ability to manipulate and collect bioparticles and macromolecules at microfabricated electrodes with ac and dc fields was further illustrated in electric field-mediated immunoassays for analyzing the biological identities of E. coli bacteria and B. globigii spores. According to these results, the electric methods for manipulating bioparticles present themselves as viable techniques for novel biomedical applications in sample preparations and biochemical assays on microelectrode arrays.

Solid-phase capture of proteins, spores, and bacteria

Current methods for the detection of pathogens in food and water samples generally require a preenrichment step that allows selective enrichment of the test organism. The objective of this research was to eliminate an enrichment step to allow detection of bacteria directly in food and water samples in 30 min. A high-flow-rate, fluidized bed to capture and concentrate large (bacteria and spores) and small (protein) molecules was developed. This format, ImmunoFlow, is volume independent and uses large beads (greater than 3 mm in diameter) when capturing bacteria to prevent sample clogging when testing food samples. Detection of bound targets was done using existing enzyme-linked immunosorbent assay (ELISA) protocols. Four antibodies (anti-Escherichia coli O157:H7, -Bacillus globigii, -bovine serum albumin [BSA], and -ovalbumin [OVA]) were covalently coupled to various glass and ceramic beads. Very small amounts of BSA (<1 ng) and OVA (0.2 to 4.0 microg) were detected. Various industrial and environmental samples were used to observe the effect of the sample composition on the capture of anti-B. globigii and anti-E. coli O157:H7 modified beads. The lower limit of detection for both E. coli O157:H7 and B. globigii was 1 spore/cell independent of the sample size. The activity of anti-B. globigii modified beads declined after 3 days. Anti-E. coli O157:H7 modified beads declined in their capture ability after 2 days in various storage buffers. Storage temperature (4 and 25 degrees C) did not influence the stability. The ImmunoFlow technology is capable of capturing bacteria and spores directly from samples, with subsequent detection in an ELISA format in 30 min.

Response of herb processing workers to work-related airborne allergens

A group of 51 herb processing workers employed in a big herb processing facility located in eastern Poland were examined by the skin and precipitin tests with, respectively, 4 and 17 extracts of microorganisms associated with organic dusts. Out of this number, 32 workers were examined by the skin test with 7 extracts of selected herbs processed in the facility. All the subjects were asked about the occurrence of work-related symptoms. 32 healthy office workers were examined with microbial extracts as a reference group. The herb processing workers showed a high proportion of early skin reactions (after 20 min) to the extract of Gram-negative bacterium Alcaligenes faecalis (41.2%), significantly higher compared to the reference group (p<0.01). At all time intervals (20 min, 8 hrs, 24 hrs), the workers responded with a high frequency to the extract of Bacillus subtilis (respectively 72.5%, 64.7%, and 15.7%), significantly greater compared to the reference group (respectively p<0.001, p<0.001, and p<0.05). No significant differences were found between the groups of herb processing workers and referents in skin response to the extracts of Streptomyces albus and Alternaria alternata and, except for the extract of Pantoea agglomerans, in the frequency of positive precipitin reactions to microbial antigens. In the skin test with herb extracts, the highest response among workers were caused by the extracts of chamomile flowers and nettle leaves which evoked 40-65% of positive skin reactions at all time intervals. 39 out of 51 interviewed herb processing workers (76.5%) reported the occurrence of work-related general, respiratory and skin symptoms. The positive skin reactions occurred more frequently among symptomatic workers which suggests that the specific immunologic response might be implicated in etiopathogenesis of work-related symptoms in examined workers. However, in most cases the differences did not attain a significance level which indicates that there is no direct relationship between a positive immunologic response and the appearance of symptoms caused by occupational exposure to herb dust, and that most probably a considerable part of these symptoms might be also due to non-specific immunologic and/or toxic mechanisms.

Adverse reactions to anthrax immunisation in a military field hospital

OBJECTIVE

To determine the outcome of anthrax immunisation.

METHODS

Adverse reactions (occurrence, nature, severity and incapacity) and immune responses to a voluntary programme of anthrax immunisation at 0, 3, 6, and 24 weeks were monitored by questionnaire and voluntary blood sampling in 129 members, including 24 immunised 7 years previously (immunes), of a military field hospital alerted for possible deployment.

RESULTS

Follow-up was complete in 85%. Ninety-eight (76%) received the first anthrax immunisation. Uptake was greater (p = 0.015) in immunes. Initial prevalence of adverse reaction was 63%. Subsequent uptake and adverse reaction dwindled significantly (p < 0.001). Only 28 (22%) were immunised at 24 weeks. Proportions reporting adverse reactions following the initial immunisation were greater in immunes (p = 0.046) and officers (p = 0.02). There was no significant (p = 0.36) correlation between uptake of immunisation and prevalence of adverse reaction. Antecedent adverse reaction did not reduce the proportion of participants accepting immunisation subsequently. The nature of adverse reactions (47% local, 24% systemic and 27% both) and severity were the same throughout. Forty-five percent of adverse reactions caused incapacity. Seventy-four percent of these had pain in the injected arm (+/- systemic symptoms) which prevented lifting or driving for 48 hours in 63%. Immune responses were greater in immunes.

CONCLUSIONS

It was concluded that anthrax immunisation results in a higher than expected prevalence of adverse reaction with initial incapacity of military significance affecting 18%. Greater immune responses may increase adverse reaction but this does not affect acceptance of anthrax immunisation. Poor completion rates necessitate development of a new anthrax immunisation strategy.

Influence of a poly-ethylene glycol spacer on antigen capture by immobilized antibodies

The use of spacers to distance an immobilized antibody from the surface of a support matrix introduces flexibility, which can reduce steric interferences between antibodies leading to a higher antigen capture efficiency. In this paper we investigated the use of a spacer molecule, poly-ethylene glycol (PEG), between the matrix surface and antibodies for the capture of Bacillus globigii, E. coli O157:H7, and ovalbumin. The antigen capture efficiency was determined using a surface ELISA method. Antibodies against the antigens were covalently immobilized either directly or via PEG to glass surfaces using a one-step EDC reaction. The amount of antibody immobilized was determined before blocking the nonspecific binding sites with bovine serum albumin. Antibodies immobilized via a PEG spacer showed a higher capture efficiency compared to direct immobilization, which was more pronounced with large antigens. Antibodies immobilized on glass supports were stable at 65 degrees C for at least 80 min, and the capture efficiency increased with heating at 65 degrees C for 20 min.

Molecular recognition specificity of Bacillus globigii spore antibodies

Western blotting methods have been used to assess the specificity of polyclonal antibodies raised against Bacillus globigii spore and vegetative cell preparations. None of the antibodies studied were completely species-specific in their recognition of spore surface epitopes. One polyclonal serum recognized several spore surface epitopes and demonstrated limited cross-reaction with the spore surface of the near-neighbour species B. subtilis. A second polyclonal serum, raised against aged spore antigens, recognized damaged spore epitopes primarily. Both of these antibodies also cross-reacted with vegetative cell epitopes present in all four Bacillus species (B. globigii, B. subtilis, B. cereus and B. anthracis) studied.

Establishment of monoclonal antibodies specific for Bacillus subtilis DB9011

Bacillus subtilis DB9011 is a strain with useful functions for agriculture. To establish a method for the discrimination of this strain from others, monoclonal antibodies (MAbs) were prepared. Although two established MAbs (MAb9B6 and MAb14D2) cross-react with some other Bacillus strains in ELISA, only B. subtilis DB9011 vegetative cells are recognized by both MAbs. MAb14D2 recognizes flagellin, a 34-kDa unit protein of flagella. The two MAbs established will provide powerful tools with which detailed analysis of this bacterial strain can be obtained under environmental conditions.

Isolation of cilia-associated respiratory (CAR) bacillus from pigs and calves and experimental infection of gnotobiotic pigs and rodents

Filamentous, gram-negative bacteria morphologically similar to cilia-associated respiratory (CAR) bacillus of rodents and rabbits were isolated from the tracheas of 5 pigs and 4 calves. All pigs but none of the calves had histologic lesions of chronic tracheitis. In silver-stained histologic sections, CAR bacilli were adhered to the tracheal epithelium of each pig but were not found in the calves. Like CAR bacillus of rats, the bacteria displayed gliding motility and grew only in cell culture or cell culture medium supplemented with fetal serum. Initially, all isolates were contaminated by Mycoplasma spp. This contamination was eliminated from 4 pig isolates by limiting dilutions, and mycoplasma-free isolates were used to intranasally inoculate gnotobiotic pigs and CAR bacillus-free mice and rats and to immunize guinea pigs. The gnotobiotic pigs remained healthy, and when they were necropsied 4 and 7 weeks after infection no macroscopic or microscopic lesions were found in the respiratory tract. However, CAR bacillus was isolated at both times from the nasal cavities and tracheas of inoculated pigs, and the ciliated tracheal epithelium of infected pigs necropsied 7 weeks after infection was colonized by low numbers of CAR bacillus-like bacteria. The rats and mice remained healthy through week 12 postinoculation, and evidence of short- or long-term colonization was not detected by histologic examination or culture. When used as primary antibody for immunohistochemical staining, sera from guinea pigs immunized with pig CAR bacillus specifically stained CAR bacilli colonizing the respiratory epithelium of naturally infected pigs, whereas sera collected prior to immunization failed to react with the bacteria. These results indicate that CAR bacilli are unlikely to be primary pathogens of pigs or cattle and that rodents do not act as reservoirs.

Effect of Bacillus firmus on antibody formation after mucosal and parenteral immunization in mice

Immunostimulatory properties of B. firmus, a nontoxic, nonpathogenic G + bacterium of external environment, were described previously. Antiinfectious and antitumor activity, macrophage activation and strong polyclonal stimulation of B lymphocytes were proved in human, mice and rats. The adjuvant effect of B. firmus on specific antibody response to ovalbumin in BALB/c mice is the topic of the present study. Against our expectation, B. firmus exerts more suppressive than stimulatory effect on specific antibody response. Formolized B. firmus decreased anti-ovalbumin response after subcutaneous immunization and only slightly increased serum antibodies after intraperitoneal immunization. After mucosal immunization, both oral and rectal, ovalbumin itself did not cause a significant systemic response but induced IgA anti-ovalbumin response in the intestine. B. firmus applied together with ovalbumin increased systemic serum response but absolutely eliminated intestinal response. The rectal route of antigen administration has been found less convenient because of less precise dosing of antigen in this mode of immunization.

Stimulation of macrophages by Bacillus firmus: production of nitric oxide and cytokines

Immunostimulatory properties of gram-positive Bacillus firmus were investigated under in vitro conditions using murine peritoneal macrophages. B. firmus stimulated in a concentration and time dependent manner the secretion of tumour necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10), but it had no influence upon interferon-gamma (IFN-gamma) and interleukin-2 (IL-2) production. It also substantially augmented production of nitric oxide (NO) induced by exogenous IFN-gamma. Inhibitory experiments using neutralizing antibodies against TNF-alpha and/or IL-10 have demonstrated that these cytokines are responsible for triggering the underlying mechanism(s) leading to enhanced NO production. The cytokine-stimulatory and NO-costimulatory properties could participate in the antiinfectious and anticancer effects of B. firmus, detected previously in the in vivo experiments.

[The antitumor activity of vaccines obtained by using a culture broth filtrate of Bac. mesentericus AB-56 or antibiotic AB-56]

The possibility of the purified antibiotic, extracted from the Bac. mesentericus AB-56 culture liquid, application for the antitumoral vaccine preparation and standardization was established in experiment, conducted on the mice of Balb/c line.

Antigenic analyses of cilia-associated respiratory (CAR) bacillus isolates by use of monoclonal antibodies

Mouse monoclonal antibodies (MAbs) developed to a rat isolate (R-3) of cilia-associated respiratory (CAR) bacillus were used to assess antigenic relationships among three rat and five rabbit CAR bacillus isolates. Evaluation of MAbs by enzyme-linked immunosorbent assays (ELISAs) indicated that 87 of 241 hybridomas secreted CAR bacillus-reactive antibodies that could be grouped into four major groups. Group-I MAbs reacted with epitopes expressed by all CAR bacillus isolates and at least two or more nonrelated species of bacteria. Group-II, -III, and -IV MAbs reacted with only one or more of the rat CAR bacillus isolates; no MAbs reacted only with rat and rabbit CAR bacillus isolates. Western blot analyses indicated that 41-, 50-, and 105-kDa peptides of rat CAR bacillus isolates expressed rat CAR bacillus group- and isolate-specific epitopes. Hyperimmune anti-CAR bacillus antiserum and serum specimens from a CAR bacillus histologically positive mouse and rat also reacted with the 41-, 50-, and 105-kDa peptides. Sera from CAR bacillus histologically negative rats did not react with these peptides. These results suggest that the 41-, 50-, and 105-kDa peptides may represent suitable antigens for development of a specific ELISA for detection of rodent CAR bacillus infections. Furthermore, these data indicate that use of crude CAR bacillus preparations for either rat or rabbit CAR bacillus ELISAs is inappropriate.

Bacillus licheniformis sigB operon encoding the general stress transcription factor sigma B

The general stress response of the Gram-positive soil bacterium Bacillus subtilis is controlled by the sigma B transcription factor. sigma B activity is regulated by the newly discovered partner switching mechanism of signal transduction, which integrates the two different classes of challenges which posttranslationally activate sigma B: environmental stress and energy stress. Our investigation of a possible sigma B homologue in the related soil bacterium B. licheniformis had two goals. First, this study would contribute to understanding the distribution of the sigma B general stress system among Gram-positive bacteria. Second, a phylogenetic comparison of regulatory systems can supplement genetic and biochemical analysis by revealing conserved features that are critical for function. We report here that (1) B. licheniformis cells contain a protein that closely resembles B. subtilis sigma B in size and antigenic properties; (2) the level of this potential sigma B homologue rapidly increases following environmental or energy stress; and (3) the B. licheniformis genome encodes a homologue of the sigB general stress operon, including the sigma B structural gene and seven rsb regulatory genes. Based on these results, B. licheniformis possesses a general stress system likely regulated by two coupled partner switching modules that sense and integrate the two broad classes of activating stress signals.

Immunomodulatory effects of Bacillus firmus

3-day-old miniature piglets were stimulated in vivo with Bacillus firmus by the intraperitoneal or intragastric route for 1 d. Cells containing IgA and IgG2 were detected in the ileum in all stimulated but not in control animals. The frequency of blood CD3+ cells increased after intraperitoneal administration of B. firmus, the ratio of polymorphonuclears to lymphocytes increased in all stimulated piglets. B. firmus induced antitumor immunity in rats with transplanted Yoshida sarcoma cells. Granular lymphocytes and dead tumor cells were found in peritoneal exudate of stimulated animals. B. firmus induced IFN-gamma synthesis in human blood lymphocytes stimulated in vitro for 1 d. The amount of TNF-alpha produced by these stimulated human peripheral blood mononuclears (PBMC) was lower than that of PBMC stimulated with some other bacterial immunomodulators. Cells containing TGF-beta or IL-8 were not found in human PBMC stimulated with B. firmus.

Structure of genes for cecropin A and an inducible nuclear protein that binds to the promoter region of the genes from the silkworm, Bombyx mori

Cecropins are a family of antibacterial peptide synthesized in insects as a response to bacterial infection. To study the regulation of the immune genes in insects, two cecropin A genes were cloned and sequenced from the silkworm, Bombyx mori. The two genes, CecA1 and CecA2, encoded identical preprocecropin A, having one intron of 609 bp and 929 bp, respectively. The 5'-upstream regions of the genes contained a NF-kappa B like element and IL-6-RE Type I element. Electrophoretic mobility shift assay revealed that a nuclear protein of fat body which specifically bound to the kappa B-like element was activated by injection of the larvae with peptidoglycan.

Molecular biology of S-layers

In this chapter we report on the molecular biology of crystalline surface layers of different bacterial groups. The limited information indicates that there are many variations on a common theme. Sequence variety, antigenic diversity, gene expression, rearrangements, influence of environmental factors and applied aspects are addressed. There is considerable variety in the S-layer composition, which was elucidated by sequence analysis of the corresponding genes. In Corynebacterium glutamicum one major cell wall protein is responsible for the formation of a highly ordered, hexagonal array. In contrast, two abundant surface proteins from the S-layer of Bacillus anthracis. Each protein possesses three S-layer homology motifs and one protein could be a virulence factor. The antigenic diversity and ABC transporters are important features, which have been studied in methanogenic archaea. The expression of the S-layer components is controlled by three genes in the case of Thermus thermophilus. One has repressor activity on the S-layer gene promoter, the second codes for the S-layer protein. The rearrangement by reciprocal recombination was investigated in Campylobacter fetus. 7-8 S-layer proteins with a high degree of homology at the 5' and 3' ends were found. Environmental changes influence the surface properties of Bacillus stearothermophilus. Depending on oxygen supply, this species produces different S-layer proteins. Finally, the molecular bases for some applications are discussed. Recombinant S-layer fusion proteins have been designed for biotechnology.

Monoclonal antibodies for use in detection of Bacillus and Clostridium spores

Five monoclonal antibodies against bacterial spores of Bacillus cereus T and Clostridium sporogenes PA3679 were developed. Two antibodies (B48 and B183) were selected for their reactivity with B. cereus T spores, two (C33 and C225) were selected for their reactivity with C. sporogenes spores, and one (D89) was selected for its reactivity with both B. cereus and C sporogenes spores. The isotypes of the antibodies were determined to be immunoglobulin G2a (IgG2a) (B48), IgG1 (B183), and IgM (C33, C225, and D89). The antibodies reacted with spores of B. cereus T, Bacillus subtilis subsp. globigii, Bacillus megaterium, Bacillus stearothermophilus, C. sporogenes, Clostridium perfringens, and Desulfotomaculum nigrificans. Antibody D89 also reacted with vegetative cells of B. cereus and C. sporogenes. Analysis of B. cereus spore extracts showed that two of the antigens with which the anti-Bacillus antibodies reacted had molecular masses of 76 kDa and approximately 250 kDa. Immunocytochemical localization indicated that antigens with which B48, B183, and D89 react are on the exosporium of the B. cereus T spore. Antibody D89 reacted with the exosporium and outer cortex of C. sporogenes spores in immunocytochemical localization studies but did not react with extracts of C. sporogenes or B. cereus spores in Western blotting. Some C. sporogenes antigens were not stable during long-term storage at -20 degrees C. Antibodies B48, B183, and D89 should prove to be useful tools for developing immunological methods for the detection of bacterial spores.

Immunoreactivity of allergen (Bet v 1) conjugated to crystalline bacterial cell surface layers (S-layers)

BACKGROUND

Crystalline cell surface layers (S-layers) from Gram-positive eubacteria had been demonstrated as carrier/adjuvants for chemically synthesized tumor-associated oligosaccharide haptens and capsular polysaccharide antigens of Streptococcus pneumoniae strains.

OBJECTIVES

The applicability of S-layers as vaccine carrier for treatment of Type I allergy was investigated.

STUDY DESIGN

Native or cross-linked S-layer self-assembly products and cell wall preparations from Bacillus sphaericus CCM 2177 and Thermoanaerobacter thermohydrosulfuricus L111-69 and L110-69 were used for immobilization of recombinant major birch pollen allergen Bet v 1.

RESULTS AND CONCLUSIONS

Depending on the carrier used, amounts of approximately 20-40 micrograms allergen per mg conjugate could be immobilized. By application of L-glutamic acid dimethyl ester as a spacer, this value could be increased approximately 10-fold. The functionality of the rBet v 1-conjugates was assessed in immunological systems. (i) The presence of intact B-cell epitopes was demonstrated in inhibition experiments using human Bet v 1-specific IgE. (ii) The rBet v 1-S-layer conjugates were immunogenic in mice. (iii) The proliferation of rBet v 1-specific T-cell clones suggested that the peptides created by processing of immobilized Bet v 1 were similar to those derived from natural allergen. (iv) Stimulation of human allergen-specific TH2 lymphocytes with S-layer-conjugated Bet v 1 led to a modulation of the cytokine production pattern from TH2 to TH0/TH1. This study indicates that S-layers may be suitable carriers for few immunotherapeutical vaccines for Type 1 hypersensitivity.

Polyclonal activation of human lymphocytes by Bacillus firmus and its constituents

Bacillus firmus strongly stimulates Ig synthesis in the cultures of human peripheral blood mononuclear leukocytes. As apparent from the character of Ig formation and blastic transformation, the stimulation has features of a polyclonal activation of B lymphocytes without substantial participation of T lymphocytes. B firmus is a strong B cell polyclonal activator even for human cord blood lymphocytes. The most striking feature is the strong stimulation of IgA synthesis in both adult and cord blood lymphocytes. Several crude fractions were isolated from B. firmus. None of them exhibited any remarkable enhancement of activity but the cytoplasmic fraction P-40 was clearly more potent than the intact bacilli. On the other hand, cell wall peptidoglycan, a well known polyclonal activator of B cells, had a much lower activity than whole bacteria. The effect of B. firmus on the stimulation of Ig formation is thus relatively complex; it is not caused mainly by peptidoglycan but rather by some cytoplasmic constituents of the bacterium.

The regulatory C proteins from different restriction-modification systems can cross-complement

The BamHI restriction-modification system contains a third gene, bamHIC, which positively regulates bamHIR. Similar small genes from other systems were tested in vivo for their ability to cross-complement. C.BamHI protein was identified, purified, and used to raise polyclonal antibodies. Attempts to detect other C proteins in cell extracts by cross-reactivity with C.BamHI antibodies proved unsuccessful.

Prolonged survival of AVN Wistar rats with transplanted Yoshida sarcoma and increase of granular lymphocytes after administration of Bacillus firmus and their crude lipids

Bacillus firmus is a Gram-positive, aerobic, sporulating, nonpathogenic air contaminant which, according to earlier findings, is a strong polyclonal activator of B lymphocytes. The crude lipids of this microbe induced significant resistance of mice against listerial infection. The administration of bacterin, like that of crude lipids obtained by the extraction of cell suspension with chloroform-methanol to rats, strain AVN Wistar, transplanted later with Yoshida sarcoma, significantly prolonged the survival of the animals in comparison with the control group. At the same time the number of granular lymphocytes was increased. The destruction of tumor cells in the peritoneal exudate of immunostimulated rats was also determined.