title: Popliteal lymph node (PLN) assay to study adjuvant effects on respiratory allergy.
abstract: Different variants of the popliteal lymph node (PLN) assay have been published. Here we describe the adjuvant popliteal lymph node assay, an immune response assay to study the adjuvant activity of soluble substances as well as particulate matter. The substance to be studied for adjuvant activity is injected into the hind footpad of mice or rats together with an antigen. Adjuvant activity is determined as the increase in PLN weight and cell numbers in animals receiving antigen together with the substance under study, compared with PLN weight and cell numbers in animals given the antigen without the substance in question, and animals given the putative adjuvant alone. Because lymph node weight and cell numbers are immunologically non-specific parameters, specific immune response assays like serum antibody responses or antibody-forming cell numbers should additionally be performed. Different antigens and immune response assays may be used, depending on the research question asked. In relation to respiratory (or food) allergy, the assays should as a minimum include determination of specific IgE in serum, and preferably also IgG1 (mouse). Serum specific IgG2a antibody determination may be added to get an indication of the Th1-Th2-balance of the response. The adjuvant PLN assay, with cellular response assays performed in the draining popliteal lymph node and antibody determinations in serum, requires small amounts of test material. The assay offers a practical, sensitive and reproducible method to determine the adjuvant activity of soluble substances as well as particulate material, with the possibility to also perform mechanistic studies.
authors.affiliation: Department of Environmental Immunology, Division of Environmental Medicine, Norwegian Institute of Public Health, P.O. Box 4404 Nydalen, NO 0403 Oslo, Norway. martinus.lovik@fhi.no
authors.forename: Martinus
authors.initials: M
authors.lastname: Løvik
authors.forename: Torunn
authors.initials: T
authors.lastname: Alberg
authors.forename: Unni Cecilie
authors.initials: UC
authors.lastname: Nygaard
authors.forename: Mari
authors.initials: M
authors.lastname: Samuelsen
authors.forename: Else-Carin
authors.initials: EC
authors.lastname: Groeng
authors.forename: Per Ivar
authors.initials: PI
authors.lastname: Gaarder
mesh_terms: D000276:Adjuvants, Immunologic / Q000633:toxicity*; D000818:Animals; D004195:Disease Models, Animal; D006614:Hindlimb; D006967:Hypersensitivity / Q000276:immunology*; D023441:Local Lymph Node Assay; D008171:Lung Diseases / Q000276:immunology*; D008198:Lymph Nodes / Q000276:immunology / Q000473:pathology
chemical_list: D000276:Adjuvants, Immunologic