A recombinant non-fatty acylated form of the Hi-PAL (P6) protein of Haemophilus influenzae elicits biologically active antibody against both nontypeable and type b H. influenzae.
An approximately 15,000-dalton outer membrane lipoprotein of Haemophilus influenzae, the Hi-PAL (P6) protein, has been shown to elicit bactericidal and protective antibodies against both type b and nontypeable H. influenzae strains and is a vaccine candidate for these organisms. To determine whether the lipid modification of this protein is required for immunogenicity or the elicitation of biologically active antibodies, a genetic fusion was constructed that contains the sequence of mature Hi-PAL fused to the polylinker region of pUC19. The protein expressed by this clone does not contain detectable lipid and was purified to homogeneity. This recombinant fusion protein, rPAL, elicited a strong immune response when injected into rabbits, and the antiserum reacted well with native Hi-PAL. The antiserum was bactericidal against a number of clinical nontypeable strains, duplicating the activity of anti-Hi-PAL. The anti-rPAL antiserum was also protective against type b bacteremia in the infant rat model. These results demonstrate that purified rPAL elicits antibodies with biological activities that are similar to those of anti-Hi-PAL antibodies. Thus, the lipid component of Hi-PAL is not required for either immunogenicity or elicitation of biologically active antibodies.
Green
B A
BA
Praxis Biologics, Inc., Rochester, New York 14623.
Metcalf
B J
BJ
Quinn-Dey
T
T
Kirkley
D H
DH
Quataert
S A
SA
Deich
R A
RA
D000215:Acylation; D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis; D000911:Antibodies, Monoclonal; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000276:immunology*; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D005227:Fatty Acids / Q000276:immunology*; D006193:Haemophilus influenzae / Q000235:genetics / Q000276:immunology*; D007114:Immunization; D008969:Molecular Sequence Data; D019308:Palmitic Acid; D010169:Palmitic Acids; D021382:Protein Sorting Signals / Q000235:genetics; D011817:Rabbits; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000276:immunology
D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D001425:Bacterial Outer Membrane Proteins; D005227:Fatty Acids; D010169:Palmitic Acids; D021382:Protein Sorting Signals; D011993:Recombinant Fusion Proteins; D019308:Palmitic Acid