Ultrastructural and morphometric effect of aluminum phosphate and calcium phosphate nanoparticles as adjuvants in vaccinated mice

Abstract EN

Background/aim Calcium phosphate (CAP) and aluminum phosphate (alum) compounds have been approved as vaccine adjuvants for humans.

The present study aimed to study the ultrastructural and morphometric effect of both aluminum phosphate (alum) and CAP nanoparticle adjuvant.

Materials and methods Eighteen Swiss albino mice were used in the experiment.

An overall 50% of them were adult and the other 50% were juvenile.

Mice were immunized intramuscularly with 0.125 ml of adjuvanted tetanus toxoid vaccine.

In the alum adjuvant group, three adult mice and another three juvenile ones were injected with alum adjuvanted vaccine and killed 1 week after immunization.

In the CAP adjuvant group, three adult mice and another three juvenile mice were injected with CAP adjuvanted vaccine and killed 1 week after immunization.

At the end of the work, samples of the liver, kidney, and brain were subjected to light and electron microscopic examinations.

Results In both the alum group and the CAP nanoparticle adjuvant group, the examination revealed wide and severe ultrastructural changes in the liver, kidney, and brain of adult and juvenile mice.

These changes included swollen mitochondria with degenerated cristae, severely degenerated ground cytoplasm, and unusual chromatin picture of nucleus.

In contrast, morphometric studies of the nucleus/cell ratio and damaged areas showed a significant increase in the liver, kidney, and brain of both adjuvants.

Conclusion The results of this study revealed that both aluminum phosphate (alum) and CAP nanoparticle adjuvant caused ultrastructural and morphometric changes in tissues of the liver, kidney, and brain.