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M. PEREA FALOMIR Y COLS. ANAL. REAL ACAD. FARM.

Palabras clave: Difusión.- Antígeno.- Anticuerpo.

SUMMARY

Diffusion in the antigen - antibody reaction

In previous works some indications about the importance of molecular diffusion
in the antigen-antibody reaction have been reported. Polynomic plots were used for the
analysis of the results; They have the advantadge of being simple, but the drawback of
not giving very much information concerning the characteristics of the process.

In this work the results obtained in several series of kinetics of antigen-antibody
experiences were used. In most of them the antigen was labelled with I125and in some
cases it was the antibody, with the same radionuclide. In all cases the reaction was
followed by measuring the radioactivity of the Ag-Ab immunocomplex produced in
different times. This signal is directly proportional to the concentration, so the original
data are presented as Activity (represented by A) in CPM vs time (t) in minutes.

The results obtained for sixteen reactions were analyzed using exclusively the
integral method by means of both Stenberg and Karlsson models. Each one gives an
integrated velocity ecuation that was adapted in order to be applied to the data. A
Diffusion control was found in a high percentage of the studied cases.

Keywords: Diffusion.- Antigen.- Antibody.

INTRODUCCIÓN
Técnicas inmunoanalíticas: Radioinmunoanálisis (RIA)

En el terreno bioquímico-fisiológico es frecuente la existencia de
sustancias cuyas concentraciones en los fluidos biológicos son demasiado
bajas para ser detectadas por los métodos espectrofotométricos. Además,
muchas de ellas se encuentran mezcladas con otras de estructura muy
semejante, por lo que su determinación analítica suponía un doble reto,
ya que se necesitaba una técnica de gran sensibilidad y especificidad. En
los años 60 Yallow y Berson resolvieron el problema poniendo a punto,
para la valoración de la insulina, un método que combina la capacidad de
la radioquímica para la detección de cantidades muy pequeñas , con la
cualidad de distinguir selectivamente entre compuestos muy parecidos,
característica de las reacciones antígeno-anticuerpo.

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