Strong Adjuvant Effect Research Articles

Significance of anti-IgG antibodies obtained by immunization of rabbits with some streptococcal strains

Anti-human IgG antibodies have been found in a number of rabbit sera immunized with freshly isolated streptococci. The significance of these anti-IgG antibodies was investigated. An IgM rheumatoid factor was excluded because the antibodies to human IgG present in rabbit sera belonged to the IgG class and reacted with the different isotypes of the human 7 S IgG. No cross-reaction between streptococci and human IgG was found. The anti-IgG production could be attributed to the in vivo non-immunological binding of host IgG to the infecting streptococci, via their Fc(γ) receptors. A strong adjuvant effect of streptococci for IgG was found, and it explained the noticeable induction of anti-IgG antibodies by trace amounts of immunogen bound to streptococci. The possible induction of anti-human IgG antibodies by streptococcal cells could be an alternative explanation of the numerous cross-reactions described between streptococci and different human tissues.

Further Studies of the polysaccharide of Klebsiella pneumoniae possessing strong adjuvanticity. I. Production of the adjuvant polysaccharide by noncapsulated mutant.

In culture fluid, Klebsiella pneumoniae type 1 Kasuya strain produces polysaccharide exhibiting a strong adjuvant effect. The active substance responsible for the strong adjuvant effect of the polysaccharide isn ot its acidic polysaccharide fraction (the type-specific capsular antigen) but the neutral polysaccharide fraction. In the present study, a mutant which did not produce the type-specific capsular polysaccharide was isolated from ultraviolet-irradiated cells of K. pneumoniae type 1 Kasuya strain which had been labeled with leucine-requiring marker by selecting unagglutinable cells with the antiserum to he type-specific capsular polysaccharide. Serological tests showed that the type-specific acidic capsular polysaccharide was present neither on the cells surface nor in the culture fluid of the mutant. Electron microscopically, the mutant did not possess any capsular material. On the other hand, nearly an equal amount of neutral polysaccharide antigen as produced in culture fluids of the noncapsulated mutant polysaccharide antigen was produced in culture fluids of te noncapsulated mutant and the parent strain. The neutral polysaccharide antigen produced by the noncapsulated mutant exhibited the same degree of strong adjuvant effect on antibody response to bovine gammaglobulin in mice as that produced by the parent strain. The relationship between the neutral polysaccharide antigen in culture fluid and the O antigen of K. pneumoniae was discussed.

Adjuvant action of capsular polysaccharide of Klebsiella pneumoniae on antibody response. VIII. Its effect on the size and the number of cells of regional lymph node and other lymphoid organs.

Changes in the number of cells and the weight of various lymphoid organs of mice, such as the regional lymph node (right inguinal node), spleen, thymus, bone marrow, and peripheral blood, were followed after the subcutaneous injection of the capsular polysaccharide of Klebsiella pneumoniae (CPS-K). For comparison, the changes after injection of various polyclonal lymphocyte activators (PLA) including various preparations of bacterial lipopolysaccharide (LPS) were concurrently studied. The number of cells of all of the lymphoid organs tested and that of nucleated cells in the peripheral blood decreased significantly within a few days after injection of CPS-K, and increased later. Above all, the increase in the number of cells and in the weight of the regional lymph node was most prominent (about 10 times larger than that of the normal control). Such a marked increase in the number of cells of the regional lymph node was not induced by the injection of any preparation of LPS or any other PLA tested. The initial decrease in the number of cells after CPS-K injection was most marked and long lasting in the thymus. Although LPS prepared by Westphal's method from Escherichia coli 055 or Salmonella enteritidis exhibited a stronger decreasing effect on the number of cells of the thymus, the effect of LPS prepared by Westphal's method from E. coli O111 or that by Boivin's method from E. coli O55 was similar to that of CPS-K. It is concluded therefore that CPS-K has the ability to decrease the number of cells of various lymphoid organs, especially that of the thymus, initially after injection, which is a property in common with LPS, and CPS-K has a unique ability to increase markedly the cells of various lymphoid organs, especially those of the regional lymph node, at later stages after injection. Considering that CPS-K exhibits a much stronger adjuvant effect on the antibody response than does LPS or other polyclonal lymphocyte activators, it is suggested that this extraordinarily potent activity of CPS-K in increasing the number of cells of the regional lymph node is closely related to its strong adjuvant action.

Effects of retinoic acid on the immune system: Stimulation of T killer cell induction

Retinoic acid (RA), a vitamin A derivative with anti-tumor activity, was assayed for its effects on the immune system in mice. High doses of this compound (1000 microgram/mouse/day) have toxic effects and cause depletion on the peripheral lymphoid organs (spleen, thymus) while leaving the bone marrow cells unaffected. Both the in vivo and in vitro induction of cell-mediated cytotoxicity (CMC) to allogeneic tumor cells is stimulated at least tenfold by low doses (25--300 microgram/mouse/day) of RA while high doses suppress CMC induction. RA is shown to be a specific adjuvant for the induction of cytotoxic thymus-derived lymphocytes (T cells) and not a general T cell mitogen or adjuvant. It does not enhance the proliferative response in the mixed lymphocyte culture nor does it stimulate lymphocyte proliferation in response to the mitogens concanavalin A and phytohemagglutinin. The induction of cooperating T cells and the delayed-type hypersensitivity reaction are also not stimulated by RA. In contrast to the reported stimulatory effects of retinyl palmitate and retinyl acetate, RA does not stimulate the humoral response to erythrocytes. The strong adjuvant effects that RA has on the induction of CMC at low doses may be responsible for its anti-tumor activity.

Sera and the in Vitro Induction of Immune Responses

Abstract We have extended our studies on the role of bacterial contamination in the generation of fetal calf sera which support primary in vitro humoral responses by cultured mouse spleen cells. Gram-negative, gliding bacteria were isolated from a strongly supportive sample of fetal calf sera. Medium conditioned by the growth of these microorganisms had strong adjuvant effects in cultures of mouse spleen cells supplemented with a non supportive, deficient sera. The adjuvant and mitogenic activities of the bacterial conditioned medium were then compared to those of bacterial lipopolysaccharide from Salmonella typhosa 0901 in cultures of LPS responder and LPS nonresponder spleen cells. From the results of these comparative studies, we conclude that the active factor(s) obtained from the gliding bacteria is an adjuvant with properties very distinct from those of highly purified enteric bacterial LPS.

Liposomes in Immunology: The Immune Response Against Antigen-Containing Liposomes

Three ways of antigen administration to rabbits were compared with respect to the resulting immune responses. Antigen was administered free in solution, entrapped in liposomes or free in solution but together with empty liposomes. Liposomal material showed adjuvant activity when injected together with free antigen, but a much stronger adjuvant effect was found when antigen was injected entrapped in liposomes.

Effect of capsular polysaccharide of Klebsiella pneumoniae on host resistance to bacterial infections. I. Induction of increased susceptibility to infections in mice.

When Klebsiella pneumoniae capsular polysaccharide (CPS-K) from type 1, Kasuya strain, was injected intraperitoneally (i.p.) immediately before i.p. bacterial challenge, the survival time of mice infected with Salmonella enteritidis NUB 1 (virulent strain) was shortened and the mortality rate for mice infected with S. enteritidis NUB 31 (avirulent strain) was enhanced. The promotion of infection with S. enteritidis NUB 1 by CPS-K depended upon its dose, the effect of CPS-K being demonstrable up to as little as 0.2 mug per mouse. In the case of S. enteritidis NUB 31, the effect of CPS-K was detectable only when more than 20 mug per mouse was injected. As a result of enumeration of bacterial populations in the peritoneal washing, blood, liver and spleen, it was revealed that CPS-K promoted in vivo growth of S. enteritidis NUB 1 and NUB 31. In addition, CPS-K enhanced the mortality rate in mice infected with Streptococcus pyogenes or Streptococcus pneumoniae. The peak CPS-K effect on infection with S. enteritidis NUB 1 was seen when given immediately before bacterial challenge. The active substance responsible for the infection-promoting effect of CPS-K was neutral CPS-K, which is distinct from the O antigen and from acidic CPS-K (the type-specific capsular antigen). Preparations of neutral CPS-K isolated from the other three strains of K. pneumoniae exhibited a marked infection-promoting effect comparable with that of preparations from the Kasuya strain. Neutral CPS-K, with identical antigenicity to that from the Kasuya strain, has already been found to exert a strong adjuvant effect on antibody responses to various antigens in mice. No parallelism exists between infection-promoting activity and adjuvant activity of neutral CPS-K.

Interferon production in mice by the capsular polysaccharide of Klebsiella pneumoniae

The capsular polysaccharide of Klebsiella pneumoniae (CPS-K) type 1, Kasuya strain, induces interferon production in the blood of mice when injected intravenously. CPS-K resembles bacterial endotoxin (lipopolysaccharide) in the time pattern of interferon production, with peak levels 2h after injection. CPS-K on a weight basis exhibits a more potent interferon-inducing effect than lipopolysaccharide. The active substance responsible for the interferon-inducing activity of CPS-K is the neutral CPS-K antigen which is antigenically distinct from the O antigen and from acidic CPS-K (the type-specific capsular antigen). Neutral CPS-K from the Kasuya strain has been already found to exhibit a strong adjuvant effect on antibody responses to various antigens in mice. Preparations of neutral CPS-K from other strains of K. pneumoniae, of which adjuvant action is only very weak, exhibit interferon-inducing activity similar to the preparation from the Kasuya strain. Heterologous and homologous tolerance to re-induction of interferon is produced by a prior injection (one each) of LPS, neutral CPS-K, and acidic CPS-K. No simple correlation exists between the inducing and tolerogenic capabilities of these substances.

Adjuvant action of capsular polysaccharide of Klebsiella pneumoniae on antibody response. 3. Immunological and physico-chemical characterization of the active substance.

Changes in the number of cells and the weight of various lymphoid organs of mice, such as the regional lymph node (right inguinal node), spleen, thymus, bone marrow, and peripheral blood, were followed after the subcutaneous injection of the capsular polysaccharide of Klebsiella pneumoniae (CPS-K). For comparison, the changes after injection of various polyclonal lymphocyte activators (PLA) including various preparations of bacterial lipopolysaccharide (LPS) were concurrently studied. The number of cells of all of the lymphoid organs tested and that of nucleated cells in the peripheral blood decreased significantly within a few days after injection of CPS-K, and increased later. Above all, the increase in the number of cells and in the weight of the regional lymph node was most prominent (about 10 times larger than that of the normal control). Such a marked increase in the number of cells of the regional lymph node was not induced by the injection of any preparation of LPS or any other PLA tested. The initial decrease in the number of cells after CPS-K injection was most marked and long lasting in the thymus. Although LPS prepared by Westphal's method from Escherichia coli O55 or Salmonella enteritidis exhibited a stronger decreasing effect on the number of cells of the thymus, the effect of LPS prepared by Westphal's method from E. coli O111 or that by Boivin's method from E. coli O55 was similar to that of CPS-K. It is concluded therefore that CPS-K has the ability to decrease the number of cells of various lymphoid organs, especially that of the thymus, initially after injection, which is a property in common with LPS, and CPS-K has a unique ability to increase markedly the cells of various lymphoid organs, especially those of the regional lymph node, at later stages after injection. Considering that CPS-K exhibits a much stronger adjuvant effect on the antibody response than does LPS or other polyclonal lymphocyte activators, it is suggested that this extraordinarily potent activity of CPS-K in increasing the number of cells of the regional lymph node is closely related to its strong adjuvant action.

Effect of lymphocytosis-promoting factor of Bordetella pertussis on the immune response. II. Adjuvant effect for the production of reaginic antibody in the rat.

The effect of lymphocytosis-promoting factor (LPF), purified from culture fluid of <i>Bordetella pertussis, </i>on the production of IgE-type reaginic antibody was examined in the rat. Rats were immunized with dinitrophenylated <i>Ascarissuum </i>extract and injected with submicrogram doses of LPF. It was found that LPF, given either intracutaneously or intravenously, exerted a strong adjuvant effect on the production of reaginic antibody, and that the mean peak titers obtained were proportional to the dosage of LPF. Furthermore, the adjuvant activity of killed pertussis vaccine in the reaginic antibody formation correlated with its content of LPF. The results are compatible with the idea that LPF causes depletion of a certain type of lymphocyte in the lymphatic tissues that normally regulates IgE antibody response, resulting in the enhancement of reaginic antibody formation.

Virus-lipid interactions: II. The mechanism of adsorption of lipophilic viruses to water-insoluble polar lipids

In a previous paper it has been shown that certain viruses adsorb strongly to cholesterol columns and that this system is useful for the study of virus-lipid interactions. The results of adsorption studies with a greater number of different viruses and a wide range of water-insoluble polar lipids (sterols, long-chain aliphatic compounds such as acids, alcohols, amides, and amines) are reported. Data on the lipophilic affinities of different viruses, on the adsorption capacities of different lipids, and on infectivity of lipid-virus suspensions permit the following conclusions: (1) Viruses can be classified into lipophilic (influenza, NDV, vaccinia, herpes simplex, infectious canine hepatitis) and hydrophilic viruses (polio, Coxsackie, ECHO), according to their ability to interact with lipids. (2) Lipophilic viruses can be subdivided according to their differential adsorption affinities for lipids of increasing adsorption activity. (3) The strength of the bond, i.e., the reversibility of the adsorption, can be measured by determining the adsorption capacity of different lipids for a given virus and by titrating the infectivity of the corresponding lipid-virus suspensions. Of the lipids tested, hexadecylamine (HDA) is by far the most active adsorbent, capable of binding as much as 50,000 hemagglutinating (HA) units of influenza virus per milligram. In contrast to the other lipids, it combines irreversibly with virus as evident from the loss of infectivity of HDA-virus suspensions. The high adsorption capacity and binding strength of HDA for influenza virus parallels the strong adjuvant effect produced in guinea pigs immunized with HDA-adsorbed influenza vaccine.