GMP-grade pneumococcal whole-cell vaccine injected subcutaneously protects mice from nasopharyngeal colonization and fatal aspiration-sepsis.
Mucosal immunization with a killed whole-cell pneumococcal vaccine, given with enterotoxin-related adjuvants, has been shown to confer multi-serotype protection against colonization of the nasopharynx and middle ear in mice. However, because novel mucosal immunization strategies may be difficult to implement, here we evaluated subcutaneous injection. Strain RM200 was engineered to be capsule-negative, autolysin-negative, and to express a non-toxic mutant pneumolysoid. Liter-scale and 60-l Good Manufacturing Practice (GMP) cultures were grown in bovine-free soy-based medium, killed with chloroform or beta-propiolactone, and injected into C57Bl/6 mice without or with aluminum adjuvant. The adjuvant Al(OH)(3) strongly increased responses, particularly if pre-treated with phosphate. Protection was found in several tested model infections: nasal colonization with a serotype 6B strain and fatal aspiration-sepsis with strains of serotype 3 and 5. Protection against colonization was mechanistically dependent on the presence of CD4+ T cells at the time of challenge; in contrast, in the type 3 aspiration-sepsis model, CD4+ T cells were not required for protection at the time of challenge, suggesting that antibody alone was sufficient to protect against death in this model. Rabbits receiving sequential intramuscular injections in a pilot toxicity study displayed local reactogenicity at injection sites but no clinical signs. The rabbit antiserum thus produced was active in an in vitro phagocytic killing assay and passively protected mice in the type 3 aspiration-sepsis model. Approval is being sought for human trials of this vaccine.
Lu
Ying-Jie
YJ
Division of Infectious Diseases, Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
Leite
Luciana
L
Gonçalves
Viviane Maimoni
VM
Dias
Waldely de Oliveira
Wde O
Liberman
Celia
C
Fratelli
Fernando
F
Alderson
Mark
M
Tate
Andrea
A
Maisonneuve
Jean-François
JF
Robertson
George
G
Graca
Rita
R
Sayeed
Sabina
S
Thompson
Claudette M
CM
Anderson
Porter
P
Malley
Richard
R
D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000534:Alum Compounds / Q000008:administration & dosage; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D005260:Female; D007279:Injections, Subcutaneous; D051379:Mice; D008810:Mice, Inbred C57BL; D009305:Nasopharynx / Q000382:microbiology*; D011008:Pneumococcal Infections / Q000276:immunology / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage* / Q000276:immunology; D011420:Propiolactone / Q000008:administration & dosage; D011817:Rabbits; D018805:Sepsis / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*
D000276:Adjuvants, Immunologic; D000534:Alum Compounds; D022242:Pneumococcal Vaccines; D011420:Propiolactone