Several cellular and subcellular fractions were prepared from Pseudomonas aeruginosa strain PA-7. Those found to be immunogenic in rabbits included a heat-stable lipopolysaccharide, a protein-lipopolysaccharide complex, a cell wall preparation arid a formalin-killed whole cell vaccine. However, a lipopolysaccharide preparation extracted with phenol and water was found to be a poor immunogen in rabbits. The cell wall fraction proved to be the most effective immunogen in terms of the amount of antibody evoked, and of the duration of the serum antibody response. Hyperimmune sera produced against all four antigens were found to contain a mixed population of 2-mercaptoethanol sensitive and 2-mercaptdethanol resistant antibodies. Gel filtration and ion exchange chromatography studies established the presence of both IgM and IgG immunoglobulins in all four types of hyperimmune serum. Whole immune serum, as well as the IgM and IgG serum fractions, afforded passive protection to mice challenged with twenty or more LD₅₀ of viable organisms. There was an indication that the IgG fraction of two of the four serum types provided better protection than did the IgM fraction, but precipitation studies indicated that this may have been due to greater numbers of IgG immunoglobulins. In addition serum containing a high proportion of 2-mercaptoethanol resistant antibody-was found to promote faster clearance of injected bacteria than did serum taken earlier in the response. Immunodiffusion studies indicated that all four antigenic preparations contained at least one common immunogen; moreover, all serum types were able to react with sheep red blood cells coated with the heat-stable lipopolysaccharide preparation in passive hemagglutination and hemolysin tests. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate

It was established that antibodies could be evoked in rabbits against ferredoxin purified from cultures of Clostridium pasteurianum and against its performic acid oxidized derivative. The extent of cross-reaction was studied between the two antisera and four related antigens: native ferredoxin, iron-sulfide free ferredoxin, performic acid oxidized ferredoxin, arid S-carboxymethylated ferredoxin. All combinations demonstrated cross reactivity by complement fixation, and in the case of oxidized ferredoxin antiserum, three preparations, native ferredoxin, iron sulfide free ferredoxin, and performic acid oxidized ferredoxin precipitated antibody. The data obtained with these cross-reactivity studies Indicated that the cysteine-containing regions of the ferredoxin molecule were not critically involved as antigenic determinants. The C-terminal region of the protein was considered for further study. This octapeptide was synthesized and tested for its ability to combine with antibody directed against both native ferredoxin and its performic acid oxidized derivative. The peptide exhibited specific binding to both antisera as demonstrated by inhibition of complement fixation and precipitation, and by equilibrium dialysis experiments. It is suggested that C. pasteurianum ferredoxin is antigenic in rabbits, that cysteine residues are not involved in at least two of the antigenic regions of the protein, and that the C-terminal octapeptide is one of the antigenic determinants of this molecule. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate

Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 5 uppsatser.

Proefschrift--Groningen. / Includes bibliography.

Proefschrift--Groningen. / Includes bibliography.

Previous studies with conjugates containing the NH2-terminal and COOH-terminal antigenic determinants of oxidized ferredoxin from C. pasteurianum indicated a need for at least two determinants to stimulate DNA synthesis in sensitized lymphocytes. This suggested a mechanism involving cell cooperation, a possibility which has been investigated here by selectively inactivating cells binding one or the other of the determinants. Cells from immunized guinea pigs were tested in vitro for their capacity to bind antigen or to be stimulated by it before and after "antigen suicide" with radioiodinated conjugates containing the NH2-terminal or COOH-terminal determinants of oxidized ferredoxin. A microculture system for assessing antigen induced stimulation of 3H-thymidine uptake by lymphocytes was developed for this work. The data show that: 1) Lymphocytes from unimmunized guinea pigs bind both NH2-terminal and COOH-terminal determinants at a frequency of about 10-4. In immune animals the proportion of antigen binding cells increased about 4-6 fold. The frequency of cells binding the determinants depends markedly on the specific activity of antigens employed. 2) Both T and B lymphocytes bind the antigenic determinants from oxidized ferredoxin. 3) Specific inactivation of cells binding either determinant was achieved by antigen suicide with ¹²⁵I-NH₂-terminal or ¹²⁵I COOH-terminal s-BSA conjugates. Synergy occurs between the NH2-terminal binding cells and COOH-terminal binding cells in the proliferative response of sensitized lymph node cells challenged with oxidized ferredoxin in vitro. Evidence from B cell depletion studies indicates that this is a T cell-T cell interaction. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate

Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 6 uppsatser.

Thesis (Ph. D.)--Ohio State University, 2007. / Full text release at OhioLINK's ETD Center delayed at author's request.