An introduction to immunology and immunopathology.

In basic terms, the immune system has two lines of defense: innate immunity and adaptive immunity. Innate immunity is the first immunological, non-specific (antigen-independent) mechanism for fighting against an intruding pathogen. It is a rapid immune response, occurring within minutes or hours after aggression, that has no immunologic memory.

miR-155 gene: a typical multifunctional microRNA.

In the last years small RNA molecules, i.e. microRNA (miRNA) encoded by miR genes, have been found to play a crucial role in regulating gene expression of a considerable part of plant's and animal's genome.