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Biomedical subjects

J MacLennan

Publications and source records attributed to J MacLennan.

6 recordsLinked to original sources
PubMed2000

Immunologic memory 5 years after meningococcal A/C conjugate vaccination in infancy.

Infant vaccination with meningococcal conjugates may provide long-term protection against disease. Antibody levels and immunologic memory were assessed in 5-year-old Gambian children who received meningococcal A/C conjugate vaccination (MenA/C) in infancy. At 2 years, they were randomized to receive a booster of MenA/C (conjugate group), meningococcal A/C polysaccharide (MPS group), or inactivated polio vaccine (IPV group). All groups were revaccinated with 10 microg MPS at 5 years of age, as were 39 previously unvaccinated age-matched control subjects. Before revaccination, titers were higher in the conjugate and MPS groups than in control subjects (P<.001); titers for the IPV group were similar to those for control subjects. Ten days after revaccination, the conjugate and IPV groups had similar serogroup C serum bactericidal antibody titers (3421 vs. 2790, respectively). These levels were significantly higher than those in the MPS (426) and control (485) groups (P<.001). Thus, immunologic memory was sustained for > or =5 years; however, MPS challenge at 2 years interfered with a subsequent memory response.

Adult↗
PubMed2000

Salivary antibody response to vaccination with meningococcal A/C polysaccharide vaccine in previously vaccinated and unvaccinated Gambian children.

Development of salivary antibodies at the age of 4 or 5 years to group A and C meningococcal polysaccharides (MenA/C PS) was studied among Gambian children, who had received MenA/C conjugate or PS vaccine in infancy. There was also a control group of 64 age matched children. IgG, IgA, and secretory Ig concentrations were measured by enzyme immuno assay. MenA/C PS vaccine induced antibodies both in previously vaccinated and unvaccinated children. The previous vaccination had not induced long lasting IgA-mediated memory. IgA antibodies were secretory, and most of IgG was serum derived. The IgG salivary response seen was similar to the serum response.

Antibodies, Bacterial↗
PubMed1999

Immune response to revaccination with meningococcal A and C polysaccharides in Gambian children following repeated immunisation during early childhood.

Forty-two Gambian children randomised to receive two doses of meningococcal A/C polysaccharide vaccine (MPS) in infancy and either MPS (n = 15), meningococcal A/C conjugate (n = 13) or inactivated polio vaccine (IPV n = 14) at 2 years, were revaccinated with MPS at 5 years of age along with 39 matched control children. Meningococcal A and C polysaccharide antibodies were analysed by ELISA and bactericidal assay (SBA) in sera taken before and 10 days after revaccination. The geometric mean group SBA titre in the MPS group following revaccination was about half that of the unvaccinated controls (0.51 95%CI: 0.28, 0.90) for group A and less than half that of the controls for group C (0.41, 95%CI: 0.16, 1.03 P = 0.06). The group C SBA response in the conjugate group was 14-fold higher than in the MPS group (P < 0.001). Multiple doses of meningococcal polysaccharide in childhood may therefore attenuate the SBA response to both group A and group C polysaccharides. In contrast, vaccination with meningococcal A/C conjugate after MPS in infancy gives immunological memory to N. meningitidis group C.

Antibodies, Bacterial↗
PubMed1999

Adverse effects and sero-responses to an acellular pertussis/diphtheria/tetanus vaccine when combined with Haemophilus influenzae type b vaccine in an accelerated schedule.

UNLABELLED: Acellular pertussis vaccines provide protection against pertussis with few adverse effects. Differences in the reactogenicity and immunogenicity of available pertussis vaccines may be influenced by the immunisation schedule employed. We assessed responses to an acellular pertussis, diphtheria, tetanus vaccine mixed with Haemophilus influenzae type b (Hib) vaccine, (PRP-T) given at age 2, 3 and 4 months. Parents kept a symptom diary for 3 days after each immunisation. Antibodies to diphtheria, tetanus, pertussis toxin and filamentous haemagglutinin were measured by enzyme immunoassay at 2 and 5 months. Results were compared with historical controls who received a combination whole-cell pertussis, diphtheria, tetanus/PRP-T vaccine in the same schedule. A total of 262 infants were recruited, of whom 251 were fully evaluated after three doses of vaccine. Systemic and most local reactions were less frequent following the acellular combination. Fever > or = 38 degrees C was reported after only 0.6% of doses. Redness or swelling > or = 2.5 cm were unusual after the first two doses (2-5%), but rates rose to 13% after the third dose. Antibody responses to diphtheria and tetanus toxoids were lower, while those to pertussis antigens were higher, more uniform and less attenuated by pre-immunisation antibody than in infants who received the whole-cell combination. All infants achieved protective antibody titres of at least 0.1 IU/ml for diphtheria and 0.01 IU/ml for tetanus. CONCLUSION: The acellular combination vaccine was immunogenic for diphtheria, tetanus and pertussis components and was associated with low rates of fever following immunisation.

Analysis of Variance↗
PubMed1998

Effect of combination with an acellular pertussis, diphtheria, tetanus vaccine on antibody response to Hib vaccine (PRP-T).

Acellular pertussis vaccines provide protection against whooping cough with few adverse effects. Their introduction to routine immunisation programmes would be facilitated by their incorporation with other routinely administered vaccines. 262 infants were immunised with an acellular pertussis vaccine containing pertussis toxin and filamentous haemagglutinin, combined with diphtheria and tetanus toxoids. This vaccine was mixed with Haemophilus influenzae type b tetanus toxoid vaccine (PRP-T) so that infants received a single injection at age 2, 3 and 4 months. One month after the third dose the geometric mean titre of Hib IgG antibody was 0.48 microgram ml-1. Eighty-two percent of infants achieved a titre of 0.15 microgram ml-1, with only 27% achieving 1.0 microgram ml-1. This combination vaccine induced low Hib antibody responses when compared to other studies in which PRP-T was mixed with acellular or whole-cell pertussis vaccines. The combined vaccine did, however, appear to prime a subset of 35 infants for response to a fourth dose of PRP-T at 13 months of age, with a rise in GMT from 0.21 microgram ml-1 to 36.6 micrograms ml-1. These data have important implications for the introduction of combination acellular pertussis vaccines.

Antibodies, Viral↗