Surface antigen expression on bladder tumor cells induced by bacillus Calmette-Guérin (BCG): A role of BCG internalization into tumor cells

BACKGROUND

The antitumor mechanisms of bacillus Calmette-Guérin (BCG) against bladder cancer is still unclear. We previously reported that BCG was internalized by and survived within murine bladder tumor cells (MBT-2) for at least 40 days. In the present study, we investigated the effect of BCG on the surface antigen expression of bladder tumor cells and the characteristics of these cells as antigen-presenting cells in vitro.

METHODS

Surface antigen (major histocompatibility complex (MHC) Class II, CD1, CD80 and intercellular adhesion molecule-1 (ICAM-1)) expression on BCG-treated murine (MBT-2) and human (T-24, J82) bladder tumor cells were analyzed using flow cytometry. The production of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) from murine lymphocytes sensitized with BCG or BCG-treated tumor cells were also investigated.

RESULTS

The expressions of MHC Class II, CD1, CD80 and ICAM-1 were augmented in all of the bladder tumor cell lines used; however, they were augmented to varying degrees among the cell lines that were treated with live BCG. Heat-killed BCG had little or no effect. When murine lymph node cells sensitized with BCG or BCG-treated MBT-2 cells were cocultured with BCG-treated MBT-2 cells, significant amounts of IL-2 and IFN-gamma were produced in the culture medium.

CONCLUSIONS

BCG induced the augmented expression of surface antigens, such as MHC Class II, CD1, CD80 and ICAM-1, of bladder tumor cells. Furthermore, BCG-treated MBT-2 cells could stimulate BCG-sensitized lymphocytes to produce IL-2 and IFN-gamma. These results strongly suggest that bladder tumor cells gained the characteristics and functions of antigen-presenting cells (APC).

Expression of antitumor response. Role of attachment and viability of bacillus Calmette-Guérin to bladder cancer cells

BACKGROUND

Antitumor effects of Bacillus Calmette-Guérin (BCG) against superficial urinary bladder cancer is known to be strong when BCG is directly infused into the bladder cavity. For expression of that effect, attachment of BCG to tumor cells is reported to be essential as the first step. Our study was conducted to elucidate the significance of attachment of BCG to tumor cells in inducing the antitumor effect.

METHODS

BCG, Tokyo 172 strain, in the form of live bacilli, lyophilized bacilli, or autoclaved bacilli was co-cultured with MBT-2, mouse-origin transitional cell cancer cells. Various preparations of BCG were mixed with MBT-2 cells and transplanted to male C3H/He mice to see tumor growth-inhibiting effect.

RESULTS

Both live and lyophilized BCG attached strongly to MBT-2 cells. The maximal attachment to the cells with live BCG occurred 24 hours earlier than with lyophilized BCG. When BCG was autoclaved, it lost the ability to attach to the cells. Lyophilized or autoclaved BCG exerted a marked tumor growth-inhibiting effects. This effect was equal to the Tokyo 172 strain and the Armand Frappier Canada strain. Histologically, a high degree of infiltration by macrophages was seen.

CONCLUSIONS

The results indicated that coexistence of BCG, even as killed by autoclaving, with tumor cells activates local immunity. Accordingly, the significance of the attachment of BCG to tumor cells in intravesical infusion therapy is surmised to lie in the fact that it results in retention of the BCG at the reaction site. This may provide a clue on how to approach future development of safer and more stable BCG-derived antitumor drugs.

Oral recombinant Mycobacterium bovis bacillus Calmette-Guérin expressing HIV-1 antigens as a freeze-dried vaccine induces long-term, HIV-specific mucosal and systemic immunity

Induction of HIV-1-specific immune responses was evaluated using a recombinant BCG (rBCG) vector-based vaccine expressing HIV-1 Env V3 peptide (rBCG-pSOV3J1). rBCG-pSOV3J1 was manufactured as a freeze-dried preparation based on good laboratory practice guidelines. Guinea pigs were immunized with the freeze-dried rBCG vaccine by oral administration to test the effectiveness of what is generally considered the most convenient and practical route for vaccination. While delayed-type hypersensitivity (DTH) skin reactions to purified protein derivative were not detected in any of the animals receiving oral rBCG-pSOV3J1, HIV-1 V3J1 antigen-specific DTH responses were detected in all of the immunized guinea pigs 1.5 years after immunization. In addition, significant proliferative responses against HIV-1 V3J1 antigen were measured in peripheral blood mononuclear cells and splenocytes from all animals receiving oral rBCG. Interestingly, intestinal intraepithelial lymphocytes from the animals also exhibited high levels of proliferative activity against HIV-1 V3J1 antigen. These results suggest that oral vaccination of guinea pigs with freeze-dried rBCG-pSOV3J1 induces high levels of functional T cells specific for HIV-1 antigens in both mucosal and systemic compartments and suggest that this approach has potential for use as a vaccine against HIV-1.

In vitro antimycobacterial activities of pyrazinamide analogs

We synthesized various pyrazine derivatives and pyrazinamide analogs and assayed their antimycobacterial activities in vitro in order to find new drugs which are more active against Mycobacterium tuberculosis than pyrazinamide and also active against Mycobacterium avium and Mycobacterium intracellulare. Of the drugs synthesized, four drugs, namely, pyrazine thiocarboxamide, N-hydroxymethyl pyrazine thiocarboxamide, pyrazinoic acid n-octyl ester, and pyrazinoic acid pivaloyloxymethyl ester, were not only bacteriostatic but also bacteriocidal against these three species of mycobacteria in vitro under conditions in which pyrazinamide showed no or little activity. In conclusion, these four drugs are possible candidates for new antimycobacterial agents, and animal experiments are now under way.

Identification of two subpopulations of Bacillus Calmette-Guérin (BCG) Tokyo172 substrain with different RD16 regions

Two types of colonies with different morphologies (smooth: S and rough: R) formed when Bacillus Calmette-Guérin (BCG) Tokyo172 substrain was cultured on Middlebrook 7H10 agar medium, and their genotypes were analyzed by multiplex PCR on five RD regions and SenX3-RegX3. In most cases these two colony types had different genotypes, i.e., S colonies showed a characteristic 22 bp deletion in Rv3405c of the RD16 region (type I), and R colonies did not have this deletion (type II) similar to many other BCG substrains. Thus, there was a strong relationship between colony morphology and genotype. Both genotypes were found in every Tokyo172 preparation tested, including the seed lot for production, the origin of seed lot from the 1960s and ATCC BCG Japan. Type I was always in the majority. It was suggested that types I and II constituted independent subpopulations within the Tokyo172 substrain. Type I was shown to have a growth advantage over type II both on culture media and in mice organs.

BACILLUS CALMETTE-GUERIN TOKYO172 SUBSTRAIN FOR SUPERFICIAL BLADDER CANCER: CHARACTERIZATION AND ANTITUMOR EFFECT

PURPOSE

We investigated the preparation of bacillus Calmette-Guerin (BCG) Tokyo172 substrain (Japan BCG Laboratory, Ltd., Tokyo, Japan) on the characteristics of bacilli and antitumor activity in a mouse model in comparison with a preparation of the Connaught substrain (Aventis Pasteur, Ltd., Toronto, Ontario, Canada).

MATERIALS AND METHODS

Lyophilized BCG preparations of Tokyo172 and Connaught for superficial bladder cancer were tested. The number of bacilli and cfu per dose, dispersion, size and attachment to murine bladder tumor cells were determined after reconstitution. Antitumor activity was assessed by intradermal injection of tumor cells with various doses of either BCG preparation into the flanks of syngeneic mice, followed by the observation of tumor suppression and survival in mice.

RESULTS

Each dose of Tokyo172 had about half the bacilli in a dose of Connaught but the cfu content was about 13-fold higher for Tokyo172 than for Connaught. After reconstitution Tokyo172 bacilli were better dispersed with fewer aggregates than Connaught bacilli. Tokyo172 bacilli were about half as long as Connaught bacilli and Tokyo172 bacilli showed better attachment to tumor cells in vitro. In mice Tokyo172 achieved similar tumor suppression at a lower dose than Connaught.

CONCLUSIONS

High viability, good dispersion and efficient binding to tumor cells by BCG bacilli in the Tokyo172 preparation seem to be the main reasons for the lower clinical dose of this preparation compared with the Connaught preparation (18 vs 81 mg dry weight).

Lack of tuberculin activity of synthetic peptides

We synthesized an octapeptide, H-Asp-Gly-Gly-Ser-Glu-Ser-Glu-Gly-OH, and a hexadecapeptide, H-Asp-Gly-Gly-Ser-Glu-Ser-Glu-Gly-Lys-Asn-Gly-Ser-Gln-Met-Arg-Leu-OH, which corresponded to amino acids 61 to 68 and 61 to 76, respectively, of the amino acid sequence of a crystalline protein reported to be tuberculin active. Authenticity and purity of the synthesized peptides were confirmed by high-pressure liquid chromatography, amino acid analysis, mass spectrometry, and protein sequencer analysis. Tuberculin activity of the synthesized peptides was examined in guinea pigs sensitized with Mycobacterium tuberculosis or Mycobacterium bovis BCG and in tuberculin-positive healthy humans. Neither the octa- nor the hexadecapeptide was as active as tuberculin skin-test antigen.

Evaluation of the use of 5-mycoloyl-beta-arabinofuranosyl-(1-->2)-5-mycoloyl- alpha-arabinofuranosyl-(1-->1')-glycerol in serodiagnosis of Mycobacterium avium-intracellulare complex infection

5-Mycoloyl-beta-arabinofuranosyl-(1-->2)-5-mycoloyl-alpha-ar abinofuranosyl-(1-->1')-glycerol, an antigenic glycolipid from the Mycobacterium avium-intracellulare complex (MAC) was examined for its applicability to the serodiagnosis of MAC infection by ELISA. Serum IgM antibody titres against this glycolipid in healthy controls, pulmonary tuberculosis patients and sputum-MAC-culture-negative MAC patients were generally below the cut-off point (ELISA-negative), whereas most of the MAC-culture-positive MAC patient sera were ELISA-positive (93.5%) and their titres were often very high. Thus, high serum IgM titres against this glycolipid may be said to imply that the MAC disease is in an active phase.

Effective isolation of MPB64 from a large volume of culture filtrate of Mycobacterium bovis BCG Tokyo

MPB64, a secretory protein of Mycobacterium bovis BCG Tokyo, was isolated from a culture filtrate of the bacteria in Sauton synthetic medium harvested on day 8. The protein was isolated by five steps; (i) concentration of the culture filtrate by cutting the molecules smaller than 5 kDa with the Millipore Pellicon Cassette system, (ii) affinity separation by a Phenyl Sepharose CL-4B column, (iii) separation with a DEAE-Sepharose CL-6B column with 3 M urea, (iv) separation with a Sephacryl S200HR column, and (v) separation with a DEAE-Sepharose column without urea. MPB64 in each fraction was determined by comparing the band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with that of standard MPB64. The specificity of isolated MPB64 was tested by immunoblotting with anti-MPB64 antibody. The potency of isolated MPB64 in eliciting skin reaction in the BCG-sensitized guinea pigs was the same to that of standard MPB64. The method described herein is an improved one for isolating MPB64 from a large volume of culture filtrate of M. bovis BCG Tokyo. The technique should be applicable to isolation of other mycobacterial secretory proteins.

Modified multiplex PCR for identification of Bacillus Calmette–Guérin substrain Tokyo among clinical isolates

When an adverse reaction occurs and a mycobacterial species is isolated from a person vaccinated with Bacillus Calmette-Guérin (BCG) or a patient receiving BCG immunotherapy, it is essential to identify whether the isolate is BCG or another mycobacterial species. However, differentiation of BCG from other members of Mycobacterium tuberculosis complex has been very difficult. Using several specific primer-pairs, Bedwell et al. [Bedwell J, Kairo SK, Behr MA, Bygraves JA. Identification of substrains of BCG vaccine using multiplex PCR. Vaccine 2001; 19: 2146-51] recently reported that they could distinguish BCG substrains. We modified their method to improve differentiation of Tokyo 172 from other members of the M. tuberculosis complex, and examined whether this modified method could be applied to clinical isolates. Our method clearly identified BCG substrain (BCG Tokyo 172) among clinical isolates and easily distinguished between M. tuberculosis and wild-type Mycobacterium bovis.

Immunological protection induced by bacillus Calmette-Guérin treatment in a murine bladder tumor model

BACKGROUND

It has been previously reported that MBT-2 tumor growth is completely inhibited when mice are inoculated with bacillus Calmette-Guérin (BCG). In this study it was examined whether or not vaccination with a mixture of BCG and MBT-2 cells also induces immunological protection against murine bladder tumors.

METHODS

Seven hundred thousand MBT-2 cells and 1 mg of BCG (Tokyo 172 strain) per mouse were injected subcutaneously into female C3H/HeN mice. Four and eight weeks after vaccination with this mixture, animals were reinoculated with MBT-2 cells alone or MBT-2 cells cocultured with BCG.

RESULTS

Animals vaccinated with a mixture of BCG and MBT-2 cells showed MBT-2 tumor growth but completely rejected the MBT-2 cells cocultured with BCG. MBT-2 cells cocultured with BCG developed into tumors when they were inoculated into the control animals. Splenocytes prepared from vaccinated animals showed specific cytocidal activity against MBT-2 cells precultured with BCG.

CONCLUSIONS

The results suggest that a mixture of BCG and MBT-2 cells induces antitumor immunological protection against BCG- or MBT-2-associated antigens presented on MBT-2 cells precultured with BCG.

The BCG scar after percutaneous multiple puncture vaccination may help establish the nationalities of unidentified cadavers

BCG vaccination using the multiple puncture device (the Heaf gun) has been used in Japan and in the United Kingdom. The appearance of the BCG scars therefore differs from that caused by the conventional intradermal BCG vaccination, which is used throughout the world. The aim of this study was to investigate the usefulness of examining BCG scars to identify the nationalities of unidentified cadavers. We investigated the BCG vaccination program not only in Japan, but also in other countries, along with the relation between the BCG scar and nationality. The results showed that the countries which domestically make and use the Heaf gun are Japan (where it is the only method that has been in use since 1968), the United Kingdom (where it has been used, in part, since 1982), and South Africa (where it has been used, in part, since 1972). In addition, for the past 10 years, the Japanese Heaf gun method has been partially applied in the Republic of Korea and in Brazil. The Heaf gun scar can be clearly distinguished from the intradermal scar, and is visible throughout a person's life when good technique is used to administer the vaccination. If the Heaf gun scar is found on the left upper arm of an unidentified Asian cadaver, it is sure to be that of a Japanese. The findings of this present study indicate that the Heaf gun scar can be examined to identify the nationalities of unidentified cadavers.

Antibacterial activity of adriamycin against bacillus Calmette-Guerin

Although intravesical instillation of bacillus Calmette-Guerin (BCG) or adriamycin (ADR) is an established and effective therapy for superficial bladder cancer, the current major problems are BCG-resistant and ADR-resistant bladder cancer and recurrence after the instillation therapy. Combination therapy with BCG and ADR might overcome the drug-resistance of bladder cancer. However, before combined used of BCG and ADR, it should be clarified whether ADR has bactericidal and bacteriostatic effects on BCG or not, since only alive BCG has a potential antitumor effect. In the current study, the in vitro antibacterial activity of ADR was assessed on BCG by the standard serial two-fold dilution method. When BCG was treated with ADR at 0.13-125 mu g/ml for two hours, ADR had no effect on the viability and the growth of BCG. However, ADR at 250-1,000 mu g/ml had a bactericidal effect on BCG. Epirubicin (EPI) at 0.13-15.6 mu g/ml did not affect the viability and the growth of BCG, however, EPI at 31.3-1,000 mu g/ml had a bactericidal activity. Pirarubicin (THP) at 125-1,000 mu g/ml also had a bactericidal activity. The minimal inhibitory concentrations of ADR, EPI and THP were 250, 250 and 125 mu g/ml, respectively. This study demonstrates that ADR at high concentrations had bactericidal and bacteriostatic effects on BCG. These findings suggest that combination treatment with BCG and low dose ADR could be used and overcome the resistance of bladder cancer to BCG and ADR. The possible clinical implications of the combined use of BCG and ADR are discussed.

[Glycolipid-patterns of Mycobacterium tuberculosis as an aid for sub-typing]

Total lipids were extracted from Mycobacterium tuberculosis with chloroform-methanol (2:1), applied on a silica-gel thin-layer plate, and developed with chloroform-methanol-acetone (90:10:5). Glycolipids were detected by spraying Anthrone-reagent and heating. Strain H37Rv of M. tuberculosis showed four Anthrone-positive spots, namely trehalose-monomycolate, unidentified glycolipid, trehalose-dimycolate and GL-Rv, and strain H37Ra showed only two spots corresponding to trehalose-monomycolate and trehalose-dimycolate. Other 4 laboratory-stock strains of M. tuberculosis showed glycolipid-pattern identical with either of these two patterns. One hundred and fifty-eight strains of M. tuberculosis, isolated clinically from tuberculosis patients, were classified into 7 types according to their glycolipid-pattern. Twenty-seven strains contained one more Anthrone-positive spot other than those of strain H37Rv. Pattern II was most frequently observed (60 strains), and then pattern I (33 strains), VI (29 strains), IV (13 strains), V (9 strains), VII (8 strains), and III (6 strains). Pattern I corresponded to that of strain H37Ra and pattern VI corresponded to that of strain H37Rv. Glycolipid-pattern did not correlate to clinical features of patients from whom the bacilli had been isolated. A glycolipid, which moved to just under the solvent front, was a new glycolipid which has been found by us and designated as GL-Rv. Chemical structure of GL-Rv was clarified by us as trehalose-polyacyl derivatives (no mycolic acid as the acyl residue). Glycolipid-pattern was very stable and reproducible for each strain of M. tuberculosis.(ABSTRACT TRUNCATED AT 250 WORDS)

[Studies on the method to quantify PPD and its adsorption onto glass-surface]

The potency of PPD is very stable when kept as a lyophilized preparation or as a solution of high concentrations, but, as is well known, when diluted to the practical concentrations such as used in skin-testing for human, its potency diminishes rather rapidly. It has been considered that such decrease in potency is not due to denaturation of PPD, but due to its adsorption onto the surface of glass- or plastic-container. The adsorption of PPD had been studied by several authors with radiolabeled PPD or by the potency test in experimental animals or human. However, either method is not satisfactory because they are not quantitative and reproducible. Consequently, we developed a new method basing on ELISA to measure such low concentrations of PPD as used in skin-testing in human. Using this new method, we analyzed the adsorption of PPD onto glass-surface. The major characteristics of the PPD adsorption revealed by the present studies are as follows; (1) The adsorption of PPD takes place very rapidly immediately after the distribution of PPD solution to a new container and then proceeds in slower rates. (2). The rate of adsorption is influenced by both temperature and concentration of PPD solution. The rates of adsorption are almost the same at -80 degrees C and at 6 degrees C, much higher at 22 degrees C and further higher at 37 degrees C at any concentration tested. At -80 degrees C and 6 degrees C, there is no difference among the adsorption rates at three different concentrations, but at 22 degrees C and 37 degrees C, the rate of adsorption at the lowest concentration (0.25 microgram/ml) is much higher than those at higher concentrations. (3) The amounts of PPD adsorbed are determined by the surface area of glass in contact with PPD solution. (4) The larger the volume of PPD solution distributed, the bigger the absolute amount of PPD adsorbed, but the smaller the rate of adsorption. (5) So-called "volume effects" are evidenced. Commercially available Japanese PPD preparations have been produced and adjusted their potency taking such adsorption phenomena into consideration. But, if undue adsorption is induced by unappropriate handling and/or usage, the potency might be diminished. Especially, the single-dose preparation may be affected most strongly by so-called "volume-effects". Standard handling and usage recommended by the manufacturer are strictly required.