Abstract
Larvae of the Northern pine processionary moth (Thaumetopoea pinivora, TP) carry microscopic needles (setae), which by penetrating skin and mucous membranes, may cause inflammatory/immune derived symptoms in man. In the present study the stimulatory effects of setae on human blood lymphocytes in vitro was investigated. Blood mononuclear cells were separated from venous blood or buffy coat of ten healthy individuals, six previously exposed to setae and four with no known exposure. Lymphoproliferation was measured as uptake of 3H-thymidine. Setae were prepared from TP larvae. Setae and saline setae extracts stimulated proliferation of T-lymphocytes in the presence of monocytic cells. Stimulation was pronounced in cells from persons who had been exposed to setae, and weak in cells from non-exposed donors. Chitin also induced lymphocyte proliferation in most donors, but to a lesser extent and independently of donor's previous exposure to setae. In conclusion, setae contain molecules that in the presence of monocytes activate human T-lymphocytes to proliferation. The antigenic nature of stimulatory molecules was supported by the significantly stronger lymphocyte response in persons previously exposed to setae than in non-exposed donors. The nature of such molecules remains to be defined.
Highlights
IntroductionProcessionary moths with larvae that carry urticating hairs (setae) are present worldwide
Processionary moths with larvae that carry urticating hairs are present worldwide
Using phase contrast microscopy mononuclear cells were seen to adhere to setae within 24 hours of culture and some cells are stretched along the setae (Fig. 1) that had been prepared from setae mirrors of the larvae (Fig. 2A)
Summary
Processionary moths with larvae that carry urticating hairs (setae) are present worldwide. The Northern processionary moth (Thaumetopoea pinivora, TP) is mainly localised around the southern coasts of the Baltic Sea [1]. TP larvae carry setae of microscopic size (100–500 mm long and 3–7 mm in diameter), that can be released and transferred to humans and animals via air or by direct contact [2]. Setae have sharp tips that facilitate the penetration into skin or mucous membranes, thereby provoking local or general symptoms. The skin sites around setae may show itching with swelling, maculopapular redness and blister formation [3,4,5]. Inhaled setae may cause asthmatic reactions and nasal or oral contacts may give rhinitis and local inflammation. Severe gastrointestinal distress has been noted after ingestion [1]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call