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Biomedical subjects

A A McLean

Publications and source records attributed to A A McLean.

At least 19 recordsLinked to original sources

Practical considerations in the production, purification, and formulation of monoclonal antibodies for immunoscintigraphy and immunotherapy.

Issues associated with the large-scale production of monoclonal antibodies for pharmaceutical applications are examined. The development of a commercial monoclonal antibody production process involves much more than just scaling-up the laboratory process and making it cost-effective. It involves establishing the hybridoma cell bank with cells that are free of adventitious agents such as viruses and mycoplasma, that have stability in continuous culture for antibody-production rate and cell viability, and that do not have unusual or expensive media requirements. The style and mode of operation of the bioreactor used to produce the antibody must be explored. The antibody-based product must be processed to high levels of purity, and specific contaminants such as DNA and endotoxin must be reduced to extremely low levels. Appropriate labeling or drug conjugation chemistries must also be developed. The product must be formulated so that it has performance characteristics that are stable over a reasonable period of time. Adequate test procedures must be developed to assure product purity, activity, stability, and safety on a lot-to-lot-basis. Compliance with federal regulations, guidelines, and procedures must be guaranteed. In the coming decade, it is likely that the two arms of biotechnology, hybridoma technology and recombinant DNA technology, will be used together to generate unique protein molecules. These new reagents will face the same practical considerations summarized in this review.

Animals

Live Oka/Merck varicella vaccine in healthy children. Further clinical and laboratory assessment.

A clinical trial among 137 healthy children, ages 1 to 12 years, was conducted with four different doses (4,350, 870, 435, and 43 plaque-forming units [pfu]) of live Oka/Merck varicella vaccine to evaluate clinical reactions and selected laboratory parameters and to determine the minimum effective dose and induction time of antibody. The vaccine was well tolerated with no significant difference in the rate of reported symptoms by dose. The frequency of varicellalike rash was 3% (4/137); all rashes were mild. Serum aminotransferase values were essentially unchanged after vaccination. Minor variations found in platelet counts after vaccination were not associated with any bleeding, bruising, or clotting. Among initially seronegative children who received doses of 435 pfu or greater, 94% assayed at two weeks and 100% assayed at four or six weeks seroconverted. The geometric mean titers were similar for all four doses at six weeks. IgG and IgA responses were demonstrated with no relation to the vaccine dose.

Alanine Transaminase

Persistence of antibody after administration of monovalent and combined live attenuated measles, mumps, and rubella virus vaccines.

Hemagglutination-inhibiting antibodies were retained in comparable levels eight years after vaccination with Enders' original Edmonston and more attenuated Moraten (Attenuvax) and Schwarz line measles vaccines. Neutralizing antibody persisted without substantial decline in titer for at least 9.5 years after administration of Jeryl Lynn mumps virus vaccine (Mumpsvax). Antibodies were retained without important decline in children and adults for at least 7.5 and 7 years, respectively, after administration of HPV-77 duck-modified rubella vaccine (Meruvax). The patterns of antibody persistence 7.5 years after administration of combined measles-mumps-rubella (M-M-R) and mumps-rubella (Biavax) vaccines, 6 years after administration of measles-rubella vaccine (M-R-VAX), and 4 years after administration of measles-mumps vaccine (M-M-VAX) were the same as for the monovalent vaccines, indicating no alteration in the retention of immunity. Subclinical reinfection evidenced by increase in homologous antibody titer was observed to follow vaccination the same as occurs after natural infection.

Adult

Polyvalent pneumococcal polysaccharide vaccines.

A 14-valent pneumococcal vaccine has recently been licensed for general use after extensive testing in human subjects. Antibody production was satisfactory in 92% of individuals and a highly significant (76-92%) reduction was found in the rates for pneumococcal pneumonias caused by the capsular types present in the vaccine. Children over 2 years of age respond well to the vaccine, but younger children may not respond satisfactorily to some capsular types. In adults, the duration of the protective effect is at present unknown, but no substantial booster response was seen after a second dose at 1 year. Such a booster dose, in fact, induced a marked increase in the degree of local reaction at the injection site.

Antibodies, Bacterial

Seroepidemiologic investigations of human hepatitis caused by A, B, and a possible third virus.

Seroepidemiologic studies were made of normal subjects in populations in the United States and Costa Rica and in family outbreaks of hepatitis in Costa Rica. Hepatitis A affected a majority of children of very young age in Costa Rica, while such experience in persons of high socioeconomic status in the United States did not occur before middle life. Persons of low socioeconomic status (paid plasma donors) and residents and attendants of institutions for the mentally retarded showed a far greater incidence of hepatitis A antibody than did their counterparts in the open community. Hepatitis A and B epidemics occurred in families in Costa Rica with rapid spread to other susceptible members of the group. The disease was clinically apparent in roughly half the cases, whether the responsible agent be hepatitis A or B. Five cases of nonhepatitis A or B (hypothetical hepatitis C) were found and all but one of them were subclinical.

Adolescent

Long-term follow-up for immunity after monovalent or combined live measles, mumps, and rubella virus vaccines.

Antibody in human subjects persisted without substantial decline for 8 years after mumps vaccine (Jeryl Lynn), for 6 years after measles (Attenuvax), for 5 1/2 years after rubella vaccine (HPV-77 duck), for 5 years after measles-mumps-rubella and mumps-rubella combined vaccines, for 4 years after measles and rubella, and for 2 years after measles-mumps vaccines, the longest periods tested. Protective immunity against mumps illness persisted through the eighth year. The patterns for antibody following vaccination parallel those for natural infection and indicate that immunity will be lasting. Subclinical reinfection evidenced by antibody increase was commonly seen in persons who had been vaccinated, much as follows the natural infection.

Antibody Formation