Effects of intraperitoneal and intranasal application of Lentinan on cellular response in rats Nadya Markova * , Vesselin Kussovski, Tatyana Radoucheva, Krasimira Dilova, Neli Georgieva Department of Pathogenic Bacteria, Institute of Microbiology, Bulgarian Academy of Sciences, 26 G, Bonchev St., 1113 Sofia, Bulgaria Received 12 February 2002; received in revised form 24 May 2002; accepted 1 July 2002 Abstract Lentinan (Ajinomoto, Japan) was administrated intraperitoneally (i.p.) and intranasally (i.n.) at different doses (1, 5 and 10 mg/kg) to rats. Effectiveness of Lentinan treatment was evaluated by comparative testing of cell activation (establishing the number, glycolytic and acid phosphatase activity, H 2 O 2 production and killing ability against Salmonella enteritidis and Staphylococcus aureus) at two different compartments – peritoneal and broncho-alveolar cavities. The results indicated that Lentinan induced high-grade activation of peritoneal cells (PCs) and especially of broncho-alveolar cells (BACs) with markedly enhanced effector function (killing ability against S. aureus). Generally, Lentinan, known usually with its parenteral routes of application, can be successful to stimulate the host cell response in the respiratory tract by intranasal route of administration. D 2002 Elsevier Science B.V. All rights reserved. Keywords: Lentinan; Immunostimulation; Peritoneal cells; Broncho-alveolar macrophages Immunomodulation has been mainly of interest in immunopharmacology and the advance in this field has been marked by detection, isolation and assaying of new immunomodulators. Research approaches have been focused on compounds from fungi, mush- rooms and plants with immunomodulatory activity. Biologically active polysaccharides (glucans), isolated from Japanese mushroom Lentinus edodes (Shiitake), represent very interesting, nontoxic and well-tolerated immunomodulating agents. Lentinan is a classical example of Shiitake glucan isolated from fruiting body, which has marked antitumor effects mediated largely by T helper type 1 (Th1) cells and macro- phages, inducing delayed-type sensitivity response in the host cells [1–5]. Lentinan has been shown to initiate a variety of immune and inflammatory responses [4,6]. It can enhance the host resistance to bacterial, fungal, viral or parasitic infection [6–8]. Of special interest are its effects on respiratory tract cell defense mechanisms and their potential impact for preventing and treatment of pulmonary infections. The purpose of our study was to investigate how Lentinan can mobilize early host cell defense potential at two different compartments (peritoneal and bron- cho-alveolar cavities) by intraperitoneal and intranasal routes of application. 1567-5769/02/$ - see front matter D 2002 Elsevier Science B.V. All rights reserved. PII:S1567-5769(02)00140-6 * Corresponding author. Tel.: +359-981-608; fax: +359-989- 2497. E-mail address: semahead@geobiz.net (N. Markova). www.elsevier.com/locate/intimp International Immunopharmacology 2 (2002) 1641 – 1645