[Immune response to poliovirus].

General aspects on the immune response to poliovirus are described, considering it's molecular structure. Since the poliovirus is a cytocide agent, antibody immune response is the most important among those related to protection; however probably a minimum of helper T cells are required (more than 200 T lymphocytes with phenotype CD4) in order to get a best response. Phagocyte, NK cells and T lymphocytes probably take part in the viral clearance from the central nervous system, also in the host injure mechanisms.

[Evaluation of the cold chain and follow-up of the potency of the antimeasles vaccine in the field].

In order to evaluate the quality of the measles vaccine, it was carried out a study in three states of Mexico (Durango, San Luis Potosi and Yucatan) during the intensive vaccination campaign in 1986. Edmonston-Zagreb measles vaccine vials were obtained from the different administrative-sanitary levels of the Ministry of Health in Mexico. Interviews were performed to the vaccine responsibles.

[Immuno-epidemiologic considerations on the prevention of measles in Mexico].

Study results of passive natural immunity anti-measles, and immune response to measles vaccine from different strains in Mexican children under one year old, are described in this paper. Mexican infants in these studies ended their maternal immunity at 8-10 months of age. Edmonston-Zagreb (EZ) vaccine strain had higher seroconversion rates comparing to Schwarz strain.

[Evaluation of the cold chain during the national antipoliomyelitis vaccination days. Mexico, 1987-1988].

An evaluation of the cold chain used during the "National Vaccination Days Against Poliomyelitis" in January and March of 1987 and 1988 was performed in 32 states of Mexico, both the potency of the trivalent Sabin vaccine and completion of requirements for the maintenance of the cold chain were evaluated at each level in the Ministry of Health's structure. Only 56 percent of the refrigeration units exclusively stored vaccines, more than 10 percent of refrigerators were broken, and 44 percent of the persons responsible for the cold chain system considered the storage capacity inadequate. A correlation was found between non-fulfillment of maintenance requirements for cold chain and a decreased in vaccine potency.

[Seroconversion with trivalent Sabin vaccine in children less than four years of age].

A group of 58 children under 4 years old, were vaccinated with trivalent oral poliovirus vaccine Sabin (OPV), in two sanitary areas of Chiapas, Mexico. The complement of procedures for the maintenance of the cold chain, and the changes in the potency of the vaccine prior and after the vaccination were evaluated. Nurses got a blood sample of 3cc and other one, four weeks after vaccination in order to evaluate the seroconversion rate attributable to Sabin vaccine, which was analyzed through neutralization serologic test.