Research Article Immunomodulatory Activity of the Marine Sponge, Haliclona (Soestella) sp. (Haplosclerida: Chalinidae), from Sri Lanka in Wistar Albino Rats: Immunosuppression and Th1-Skewed Cytokine Response Varuni Gunathilake, 1 Marco Bertolino, 2 Giorgio Bavestrello, 2 and Preethi Udagama 1 1 Department of Zoology and Environment Sciences, Faculty of Science, University of Colombo, Colombo 3, Sri Lanka 2 Dipartimento di Scienze della Terra, Dell’Ambiente e della Vita, Università degli Studi di Genova, Corso Europa 26, 16132 Genova, Italy Correspondence should be addressed to Preethi Udagama; preethi@zoology.cmb.ac.lk Received 10 April 2020; Revised 10 July 2020; Accepted 16 July 2020; Published 16 November 2020 Guest Editor: Tomasz Baczek Copyright © 2020 Varuni Gunathilake et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Natural secondary metabolites of sponges of the genus Haliclona are associated with an array of biological activity with therapeutic usage. We investigated the immunopharmacological properties of a presumably novel marine sponge species from Sri Lanka, Haliclona (Soestella) sp. Sponge material was collected from southern Sri Lanka by scuba diving. Sponge identification was based on spicule and skeleton morphology using light microscopy. Selected in vivo and ex vivo tests investigated nonfunctional and functional immunomodulatory activity of the Haliclona (Soestella) sp. crude extract (HSCE) in the Wistar rat model. Compared to the controls, rats orally gavaged daily for 14 consecutive days with 15 mg/kg dose of the HSCE manifested a significant reduction of immune cell counts of total WBCs (by 17%; p <0:01), lymphocytes (38%), platelets (52%), splenocytes (20%), and bone marrow cells (BMC; 60%) (p <0:001), with a concurrent increase in the neutrophil : lymphocyte ratio (p <0:05); RBC counts abated by 53% (p <0:001). A significant reduction of the splenosomatic index was evident with the 10 and 15 mg/kg doses (p <0:001). Rat plasma TNF-α cytokine level was augmented by tenfold (p <0:001), IL-6 level by twofold (p <0:01) with the 15 mg/kg HSCE treatment, while IL-10 was detectable in rat plasma only with this treatment; the corresponding Th 1 : Th 2 cytokine ratio (TNF-α : IL-10) was indicative of an unequivocal Th1-skewed cytokine response (p <0:01). Ex vivo bone marrow cell and splenocyte proliferation were significantly and dose dependently impaired by HSCE (IC 50 0.719 and 0.931 μg/mL, respectively; p <0:05). Subacute toxicity testing established that HSCE was devoid of general toxic, hepatotoxic, and nephrotoxic effects. In conclusion, HSCE was orally active, nontoxic, and effectively suppressed nonfunctional and functional immunological parameters of Wistar rats, suggestive of the potential use of the HSCE as an immunosuppressant drug lead. 1. Introduction Marine pharmacognosy has gained much attention in the recent years due to the vast biological and chemical diversity of marine organisms [1, 2]. Of all marine invertebrates, marine sponges are particularly amongst the abundant reserves of novel natural products with distinct biological activity of pharmaceutical importance [3]. Several drug dis- covery and development programs are currently focused on the search for bioactive compounds from marine sponges; these organisms provide novel drug leads with antibacterial, antiviral, antifungal, antimalarial, antitumor, immunosup- pressive, and cardiovascular activity and for many other dis- eases including cancers [4]. This has resulted in the inclusion of a considerable number of sponge-derived drugs, in the global marine pharmaceutical pipeline [5]. Immune system dysfunction leads to the development of hypersensitivity reactions, autoimmune diseases, and chronic Hindawi Journal of Immunology Research Volume 2020, Article ID 7281295, 11 pages https://doi.org/10.1155/2020/7281295