Serological and biological activities of anti-Haemophilus influenzae ribosomal serum

Abstract

The antibody content in serum from rabbits immunized with ribosomes from Haemophilus influenzae type b was determined by passive hemagglutination, enzyme-linked immunosorbent assay, and complement fixation. Attempts to use passive hemagglutination to assay anti-ribosomal antibodies were unsuccessful. In the enzyme-linked immunosorbent assay tests, rabbit antiserum was allowed to react with ribosomes that adhered to microtiter plates. The enzyme-linked immunosorbent assay method detected, in two ribosome-immunized rabbits and by 3 days postimmunization, titers which rose to plateaus on days 24 to 31 and declined thereafter. With the complement fixation method, the serum from one immunized rabbit also showed a titer on day 3 and reached a plateau on days 20 to 31. Serum from the other immunized rabbit did not develop a titer until day 11; it reached a lower plateau on days 20 to 24 and then declined on days 27 to 55. Although there were no apparent differences between the two immunized rabbits by the enzyme-linked immunosorbent assay, there were differences between the complement fixation antibodies in these rabbits. Passive protection experiments were performed with these sera. Maximal passive protection was achieved when mice were challenged intraperitoneally with 100 50% lethal doses of H. influenzae and immunized intravenously 1 h later with rabbit serum collected 27 days postimmunization. Rabbit anti-ribosomal sera were evaluated for bactericidal activity. Undiluted immune sera showed bactericidal activity; however, when diluted 1:10, activity was lost. Although bactericidal activities of immune sera were correlated to passive protection activities, it is unlikely that such protection was due to bactericidal antibodies. Immune serum had opsonizing activity since it enhanced phagocytosis of H. influenzae by mouse leukocytes.

Naturally occurring antibodies in human sera that react with Haemophilus influenzae type b ribosomal vaccine

“…Ribosomal protein is the protective antigen in these preparations (12). The use of immune rabbit sera to passively immunize mice established the role of antibody in protection against challenge (2). In the present study, we have surveyed sera from human populations to determine the extent to which antibodies reacting with H. influenzae ribosomes occur naturally.…”

“…It has been reported previously that ribosomal extracts from H. influenzae induce a high degree of active immunoprotection in mice against challenge with virulent autologous or heterologous type b organisms (5,12). Antibodies induced in the rabbit by H. influenzae ribosomal preparations can passively protect mice against challenge (2). As a prelude to field trials, we have surveyed human populations to determine the incidence and titer of antibodies reacting with antigens in these ribosomal preparations to determine whether humans naturally acquire these antibodies and to assess the importance of other selected antigens in eliciting these antibodies.…”

Multiple antigenic polypeptide composed of heparanase B-cell epitopes shrinks human hepatocellular carcinoma in mice

“…To assess the anti-growth potency of the self-synthesized MAP composed of B-cell epitopes of HPSE, we administrered the tumor-bearing nude mice with the purified antiserum containing the anti-MAP polyclonal antibodies. As early as in 1981, this passive immunizing method applied on immunodeficient genetically engineered mice was approved as practical and safe by katz et al (39), as long as the volume of heterogenic antiserum used in the immunization was ≤0.2 ml.…”

Induction of active immunity with membrane fractions from Haemophilus influenzae type b

“…Capsular material does not seem to mediate this protection, since the ribosomal preparations contained less than 0.1% polyribosylribitol phosphate in ribosomes as determined by passive hemagglutination inhibition (20), and ribosomes from an unencapsulated strain also induced a high level of protection (15). The observed protection can be transferred passively by using antiribosomal serum (7).…”