Immunoprotective activity of ribosomes from Haemophilus influenzae

Abstract

Immunization with ribosomal preparations from Haemophilus influenzae type b elicited protective immunity in mice. Ribosomes from disrupted cells where isolated by differential centrifugation using sodium dodecyl sulfate. The washed ribosomes contained 25% protein and 75% ribonucleic acid and sedimented as a single peak on sucrose density gradient analysis with a sedimentation coefficient of 67S, using Escherichia coli ribosomes as a 70S marker. Immunodiffusion tests with antipolyribose phosphate serum showed that the ribosomes were free from capsular material. Mice immunized subcutaneously with ribosomes, with or without adjuvant, were challenged intraperitoneally with 100 to 1,000 mean lethal doses of H. influenzae type b suspended in gastric mucin. Significant protection was induced by ribosomes and was compared to that obtained after sublethal infection with live cells. The protection was greatly enhanced after incorporation of ribosomes into adjuvants. Maximum protection (90 to 95%) was observed at 1 to 2 weeks after immunization. Ribosomes from a nonencapsulated strain of H. influenzae were as immunogenic as those from the encapsulated strain, demonstrating that the capsular material is not responsible for immunogenicity of Haemophilus ribosomes.

Bacterial crude extracts or ribosomes are recognized similarly by peripheral and mucosal B cells

“…Specialized formations, such as Peyer's patches and solitary nodules react to foreign antigens and their stimulation results in the spreading of sensitized B cells towards all mucosal areas [17][18][19]. Ribosomes appear to trigger these mechanisms as efficiently as wild antigens, yielding increased levels of specific antibodies [3][4][5][6][7] as a consequence or the specific stimulation of B cell clones as shown in this report.…”

“…In stud-ies involving Streptococcus mutans, gnotobiotic rats fed ribosomes by gastric intubation produced Streptococcus mutans-specific antibodies in the peripheral blood and saliva [3]. In this model, as well as in others involving Streptococcus pyogenes [4], Streptococcus pneumoniae [5], Haemophilus influenzae [6] or Klebsiella pneumoniae [7], effective protection was shown to have been provided by ribosomal immunization, as demonstrated after challenge with wild bacteria. Other studies also investigated the spontaneous reactivity of human serum or salivary antibodies towards ribosomes from Streptococcus mutans [8] or Haemophilus influenzae [9], further supporting the antigenicity of ribosomal preparations and their relevance in anti-bacterial protection.…”

Serological and biological activities of anti-Haemophilus influenzae ribosomal serum

“…The H. influenzae type b strain H-2 was isolated from a fatal case of meningitis. Virulence has been maintained by serial passage in mice (10).…”

“…Ribosomes. Ribosomes were prepared by a method previously described (10). Briefly, the log phase cells of H. influenzae were washed and disrupted in a French pressure cell, and the ribosomes were extracted by using a series of differential centrifugation and treatment with 0.25% sodium dodecyl sulfate (SDS).…”

“…It has been reported that ribosomes from Haemophilus influenzae induce active immunity against a lethal H. influenzae type b infection in experimental animals; ribosomes were free from detectable capsule and cell wall components, and protein was the immunogenic moiety in these ribosomes (10,13).…”