Nitric oxide production by alveolar macrophages in response to house dust mite fecal pellets and the mite allergens, Der p 1 and Der p 2.

Background: Allergens are frequently found within or attached to particulate material. For example, house dust mite fecal pellets (HDMFP) contain the major mite allergens, exposure to which have been implicated in the development of asthma. Although several studies have examined the ability of purified allergens to generate inflammatory responses, few studies have investigated whether HDMFP per se, are biologically active.

Isolation and characterisation of a 13.8-kDa bacteriolytic enzyme from house dust mite extracts: homology with prokaryotic proteins suggests that the enzyme could be bacterially derived.

Bacteriolytic activity was detected in extracts of whole mite and spent growth medium (SGM) from the clinically important Dermatophagoides pteronyssinus and Dermatophagoides farinae mites and was most abundant in whole mite extract. Gram-positive organisms Micrococcus lysodeikticus, Bacillus megaterium and Listeria monocytogenes were preferentially lysed and the lytic activity was enhanced by thiols, destroyed by mite proteases, inhibited by HgCl2 and high concentrations of NaCl but was resistant to heat and acid treatment. Substrate SDS-PAGE analysis indicated the presence of several lytic enzymes, two of which were isolated from D.