Dendritic cells are one of the major populations of immune cells. Due to the presence of specific receptors dendritic cells (DCs) are able to respond to both intra- and extracellular antigens. The diversity of this cell population is a result of differences in localization, stage of maturation, phenotype and function. In recent years there has been a shift in perception of DCs not only as inducers of immune reactivity but also as crucial regulators of immunity, which include ability to induce and maintain tolerance and also as effector cells, which are capable to kill tumor cells (NKDCs).

Innate immunity is the first and in most organisms sole line of defence against pathogenic microorganisms. The activity of mechanisms of innate immunity starts with recognition of pathogen- associated molecular pattern (PAMP) by proteins that contain leucine rich repeats (LRR) domain. Plant proteins ‘R’ contain TIR, NBD and LRR domains and recognize specifically fungal, bacterial or viral pathogens. After pathogen detection signal cascade is initiated that results in most cases with hypersen- sitive reaction in region of infection.