Safety and Immunogenicity of a Bivalent Group B Streptococcal Conjugate Vaccine for Serotypes II and III

Abstract

To determine whether 2 monovalent group B streptococcus (GBS) serotype II or III capsular polysaccharide (CPS)-tetanus toxoid (TT) conjugate vaccines combined in a single intramuscular dose would elicit immune responses comparable to those of monovalent vaccines, 75 healthy adults were randomized to receive GBS II-TT (3.6 micro g of CPS), GBS III-TT (12.5 micro g of CPS), or a bivalent mixture of GBS II-TT/III-TT vaccine (double-masked design). Vaccines were well tolerated. Four-fold or greater increases in GBS II or III CPS-specific IgG, respectively, were noted in postimmunization serum samples from 80%-90% of bivalent conjugate vaccine recipients, and these responses were similar to those of recipients of GBS II-TT or GBS III-TT monovalent vaccines. Immune serum samples promoted the opsonophagocytic killing of types II and III GBS in vitro. Unexpectedly, some recipients of these vaccines developed cross-reactive antibodies to the structurally similar heterologous polysaccharide. These results support the feasibility of a multivalent vaccine for the 5 prevalent invasive disease-causing GBS CPS serotypes.

Alphavirus-Adjuvanted Norovirus-Like Particle Vaccines: Heterologous, Humoral, and Mucosal Immune Responses Protect against Murine Norovirus Challenge

“…Antisera from multivalent vaccination groups could also block receptor binding of evolutionarily distinct GI.1 (NV genocluster) and GII.4 (LV genocluster) VLPs (30; also data not shown), suggesting that blockade responses may be genocluster rather than strain specific and may be of particular importance when applied to the GII.4 norovirus vaccine design. Previous studies of multivalent vaccination to Neisseria and Streptococcus species induced cross-reactive antibodies that could neutralize heterologous serotypes (2,22); however, multivalent HIV envelope vaccines failed to induce cross-reactive neutralizing antibody responses (10). Together, these data support the rationale for including multiple norovirus strains from different genogroups in a comprehensive norovirus vaccine.…”

Serotipos y susceptibilidad antimicrobiana de Streptococcus agalactiae

“…En los últimos años se han evaluado vacunas en mujeres no embarazadas, que contienen antí-genos capsulares de los serotipos Ia y Ib ó II y III (en forma individual o en combinación), conjugados con toxoide tetánico, con buena capacidad inmunogénica en ensayos de fagocitosis in vitro 17,18 . Recientemente se evaluó una vacuna conjugada conteniendo polisacárido capsular del serotipo III en embarazadas de 30 a 32 semanas de gestación, siendo bien tolerada por las madres y sus hijos 29 .…”

“…La vigilancia epidemiológica de la distribución de serotipos es importante para el desarrollo y elección de vacunas conjugadas, actualmente en evaluación 17,18 .…”

Characterization of a Novel Leucine-Rich Repeat Protein Antigen from Group B Streptococci That Elicits Protective Immunity

“…However, studies carried out in the 1990s showed that conjugation of the polysaccharide to various protein carriers led to the stimulation of T-cell-dependent antigenic recognition and profound enhancement of the immunogenicity of CPS vaccines (5,6,60,61) An alternative strategy for protection against GBS infection would be to develop a vaccine with a conserved surface protein antigen. Surface antigens represent good candidates for vaccines, as antibodies directed against these targets have the potential to interfere with bacterial virulence and also to promote opsonophagocytosis through binding to ␥Fc receptors on phagocytes (17,44).…”