Seminar

Microbial glycoconjugates and eukaryotic innate immunity

Prof. Antonio Molinaro

Innate immunity is the first line of defence against invading microorganisms in vertebrates and the only line of defence in invertebrates and plants and therefore plays a crucial role in the early recognition and subsequent triggering of a pro-inflammatory response to invading pathogens. This mechanism relies on recognition of evolutionarily conserved structures on pathogens, termed microbe-associated molecular patterns (MAMPs), through a limited number of germ line-encoded pattern recognition receptors. MAMPs are characterized by being invariant among entire classes of pathogens, essential for the survival of the pathogen, and distinguishable from "self". Gram negative lipopolysaccharide and peptidoglycan are two very important cell wall glyco-conjugates and act as MAMPs in eukaryotic/bacteria interactions. Besides their general architectural principle, a number of subtle chemical variations are at the basis of the dynamic host-guest recognition that in case of pathogens is followed by the innate response and in case of symbiosis is followed by its suppression. Therefore, the structural study of such glyco-conjugates involved as virulence factors in animal or plant infections is a pivotal pre-requisite for the comprehension at molecular level of the innate immunity mechanisms. In this communication Prof. Molinaro will show some examples of isolation, structure determination and elicitation and/or suppression of plant and animal innate immunity by peptidoglycan and lipopolysaccharides from pathogen and symbiotic Gram negative bacteria.