Interaction between Salmonella enteritidis and tissue cultured macrophages derived from immunized animals

Oral Immunization in Experimental Salmonellosis II. Characteristics of the Immune Response to Temperature-Sensitive Mutants Given by Oral and Parenteral Routes

A temperature-sensitive mutant of Salmonella enteritidis, selected because of its inability to proliferate normally at 37 C, has been used as a living vaccine in mice. When given parenterally or orally, it confers a high degree of resistance against otherwise lethal S. enteritidis infections given intraperitoneally or by mouth. In contrast to most other effective living Salmonella vaccines, the temperature-sensitive mutant survives for only short periods in mouse tissues. Although the vaccine provides protection against S. typhimurium infection, possibly because of antigenic relationships between the immunizing and challenge organisms, it is ineffective against the intracellular infection caused by Listeria monocytogenes. A study of the kinetics of S. enteritidis infection in the liver and spleen of normal and immunized mice has suggested that immunity is dependent upon development of a secondary immunological response which arises approximately 7 days after introduction of the challenge infection. Although humoral antibody production forms part of this secondary response, it is not necessarily responsible for control of the infection.

Multiplication of Mycobacterium tuberculosis Within Normal and "Immune" Mouse Macrophages Cultivated With and Without Streptomycin

Acquired cellular immunity to infection with Mycobacterium tuberculosis is believed to reside in the capacity of mononuclear phagocytes of immunized animals to inhibit intracellular multiplication of the parasite. However, in macrophage tissue culture systems, it has been customary to employ streptomycin in the medium for the purpose of restricting extracellular, but not intracellular, growth of M. tuberculosis. In contrast, our data show that small amounts of streptomycin markedly inhibit intracellular as well as extracellular growth of M. tuberculosis in normal mouse peritoneal macrophages, and that the degree of this inhibition is directly proportional to the concentration of streptomycin used. In the absence of streptomycin, virulent tubercle bacilli grew as rapidly in "immune" macrophages as in normal macrophages. "Immune" macrophages, however, were slightly more resistant to destruction by the intracellularly multiplying mycobacteria. In the presence of streptomycin, however, intracellular mycobacterial growth was inhibited more in "immune" macrophages than in normal macrophages, and this effect also was directly proportional to the concentration of streptomycin used. Virulent mycobacteria grew somewhat more slowly within mouse peritoneal macrophages obtained after induction of a peritoneal exudate with glycogen than in noninduced cells. The rate of multiplication, though, was the same within normal and "immune" induced peritoneal cells except in the presence of streptomycin. As with noninduced macrophages, this drug inhibited the intracellular multiplication of virulent tubercle bacilli more effectively within "immune" induced than within normal induced cells. It would appear, therefore, that the greater inhibition of intracellular multiplication of virulent tubercle bacilli in "immune" macrophages in tissue culture noted by a number of investigators in the past may have been an artifact created by the use of streptomycin in the tissue culture medium.

Passive transfer of immunity to typhoid by macrophages

Saito, Kazuhisa (Keio University School of Medicine, Tokyo, Japan), Masayasu Nakano, Takehisa Akiyama, and Daizo Ushiba. Passive transfer of immunity to typhoid by macrophages. J. Bacteriol. 84:500-507. 1962.-Cultured peritoneal macrophages collected from mice which had been injected intravenously with intact macrophages of mice immunized with live vaccine were found to exert inhibitory action against intracellular virulent Salmonella enteritidis. This inhibition was quantitatively inferior to that exhibited by peritoneal macrophages from the donors, i.e., mice actively immunized with live vaccine. After an intravenous injection of P(32)-labeled macrophages into mice, almost no radioactivity could be recovered in the peritoneal exudate cells of the recipients; about 50% of the radioactivity was recovered from the liver, spleen, and mesenteric lymph nodes. Therefore, the inhibitory action of the recipient's peritoneal macrophages against intracellular multiplication was attributed to the capacity of the recipient's own macrophages and not to that of the donor's macrophages. Tissue-cultured macrophages from recipients of sonic-treated cells did not exhibit inhibition against intracellular, virulent S. enteritidis, although the recipients were resistant to intraperitoneal infection with the same strain.

Immunity to Salmonella infection

The foregoing literature review and data presentation have been set forth in the hope of clarifying some complex and confusing issues in regard to Salmonella infection. From a practical point of view, the information presented has implications for the direction to take with regard to improving the current typhoid vaccine, as the presently used acetone-killed cell preparation has considerable toxicity. The issues are important from a theoretical standpoint, because they have bearing on the nature of the concepts researchers and clinicians carry as working hypothesis with regard to the mechanisms of immunity to Salmonella infection. An incomplete appreciation of the literature seems to have led many scientists to believe that only cellular immunity can protect a mouse, and by analogy a human, against Salmonella. The logical deduction from such a premise is that only live vaccines will be effective in humans againsT S. typhi. Such a conclusion would appear unfounded, as documented in this review, for killed vaccines have been shown to be highly effective in vaccinating many mouse strains, as well as humans, against enteric fever.

Activity of macrophage and neutrophil cellular fractions from normal and immune sheep against Listeria monocytogenes

Cellular immunity to Listeria monocytogenes infection was studied by assaying for antibacterial activity in fractions of leukocytes collected from the peritoneal cavity, lungs, and mammary glands of immunized sheep. The cells were collected in populations that were largely either macrophages or neutrophils. Mechanically disrupted cells were divided into nuclear, lysosomal, and supernatant fluid fractions and then subjected to freezing and thawing. Comparison with similarly treated rabbit cells showed that greater fragility exists in the lysosomes of sheep cells, as indicated by the amount of acid phosphatase activity released. Inhibition of bacterial growth was assayed in a broth medium at pH 4.6. As expected, nuclear and lysosomal fractions from neutrophils were inhibitory. Some antibacterial activity was found in nuclear fractions of macrophages. The lysosomes of macrophages collected from the peritoneal cavity and the mammary gland did not inhibit the growth of L. monocytogenes. Peritoneal macrophages were allowed to interact with sensitized lymphocytes and an avirulent strain of L. monocytogenes for 4 hr prior to disruption and fractionation, but antibacterial activity was not detected. Pulmonary alveolar macrophages from 5 out of 16 sheep contained Listeria inhibitory activity in their lysosomes. The mechanism was inhibitory but not bactericidal.

Expermental salmonellosis. XI. Induction of cellular immunity and formation of antibody by transfer agent of mouse mononuclear phagocytes

When mice were injected intraperitoneally with a ribonucleic acid (RNA) preparation extracted from the peritoneal mononuclear phagocytes (termed monocytes) of immunized mice, these macrophages developed cellular immunity and cellular antibodies. The peritoneal monocytes were obtained from normal mice and maintained in tissue culture bottles in a homogeneous cell population. When they were treated in vitro with an immune RNA preparation, they acquired cellular immunity, and cellular antibodies were detectable in such monocytes. These results suggest that the mononuclear phagocytic cell line constitutes a cell line responsible for antibody formation.

Host-parasite relations in mouse typhoid

The development of acquired resistance to Salmonella typhimurium has been studied in mice infected intravenously with small numbers of streptomycin-sensitive or streptomycin-resistant organisms. By the 14th day of a primary infection the mouse develops a mechanism capable of destroying completely a super infecting dose of organisms, but is unable to eliminate organisms of the primary infection. The latter are constantly returned to the circulation from necrotic foci at the sites of implantation. Passive transfer of serum from actively infected or vaccinated animals, and immunization with heat-killed organisms, increase the capacity of the host to clear organisms from the blood, but do not interfere to any significant extent with their subsequent multiplication in the tissues. It is concluded that the resistance of actively infected animals depends on a nonhumoral mechanism capable of destroying organisms from endogenous or exogenous sources.

Characterization of "clearance" factor and "cell-bound" antibody in experimental typhoid

Daizo, Ushiba (Keio University School of Medicine, Tokyo, Japan), Taiji Nakae, Takehisa Akiyama, and Yoshio Kishimoto. Characterization of "clearance" factor and "cell-bound" antibody in experimental typhoid. J. Bacteriol. 91:1705-1712. 1966.-The "clearance" factor produced in the serum of rabbits immunized with a killed vaccine of an S-type virulent strain of Salmonella enteritidis was identified as O agglutinin and characterized immunochemically as a class of macroglobulin with a sedimentation coefficient of 12.7S. The macroglobulin, which was isolated by means of diethylaminoethyl cellulose column chromatography and sucrose density gradient centrifugation, showed a single protein peak when subjected to cellulose acetate electrophoresis and analytical ultracentrifugation. Its activity as agglutinin and "clearance" factor was inactivated both by mercaptoethanol treatment and absorbtion with the specific O antigen. The H agglutinin was also isolated as a single globulin fraction with relatively low molecular weight, and was characterized as a 7S gamma-globulin. This fraction had no "clearance" activity. A macroglobulin, similar to that identified in the rabbit serum, was extracted with urea from the cells of mice immunized with the S-type killed vaccine, but not from mice immunized with a live vaccine (R-type mutant), although this latter vaccine is very effective in producing a solid immunity against typhoid disease. The relation of this "cell-bound" antibody to the mechanism of "cellular" immunity in experimental typhoid is discussed.