The host defense peptide LL-37 is detected in human parotid and submandibular/sublingual saliva and expressed in glandular neutrophils.
Daniel Svensson, Alexandra Aidoukovitch, Emma Anders, Birgitta Agerberth, Fredrik Andersson, Eva Ekblad, Dan Ericson, Daniel Nebel, Ulrikke Voss, Bengt-Olof Nilsson
Author Information
Daniel Svensson: Department of Experimental Medical Science, Lund University, Lund, Sweden.
Alexandra Aidoukovitch: Department of Experimental Medical Science, Lund University, Lund, Sweden.
Emma Anders: Department of Experimental Medical Science, Lund University, Lund, Sweden.
Birgitta Agerberth: Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institute, Karolinska University Hospital, Huddinge, Sweden.
Fredrik Andersson: Regional Laboratories Region Skåne, Department of Pathology, Skåne University Hospital Lund, Lund, Sweden.
Eva Ekblad: Department of Experimental Medical Science, Lund University, Lund, Sweden.
Dan Ericson: Department of Cariology, Faculty of Odontology, Malmö University, Malmö, Sweden.
Daniel Nebel: Department of Experimental Medical Science, Lund University, Lund, Sweden.
Ulrikke Voss: Department of Experimental Medical Science, Lund University, Lund, Sweden.
Bengt-Olof Nilsson: Department of Experimental Medical Science, Lund University, Lund, Sweden. ORCID
The human host defense peptide, LL-37, is an important player in the first line of defense against invading microorganisms. LL-37 and its precursor, hCAP18, have been detected in unstimulated whole saliva but no reports showing hCAP18/LL-37 in isolated, parotid, and/or submandibular/sublingual saliva have been presented. Here, we measured the levels of hCAP18/LL-37 in human parotid and submandibular/sublingual saliva and investigated the expression of hCAP18/LL-37 in parotid and submandibular gland tissue. Parotid and submandibular/sublingual saliva was collected from healthy volunteers, and the levels of hCAP18/LL-37 in saliva were analyzed by dot blot, ELISA, and western blotting. Cellular expression of hCAP18/LL-37 in human parotid and submandibular glands was investigated by immunohistochemistry. Immunoreactivity for hCAP18/LL-37 was detected in both parotid and submandibular/sublingual saliva of all individuals. The concentration of hCAP18/LL-37 was similar in parotid and submandibular/sublingual saliva, and was determined by densitometric scanning of each dot and normalization to the total protein concentration of each sample, and by ELISA. Double immunohistochemistry revealed that intravascular neutrophils of both parotid and submandibular glands express hCAP18/LL-37. For the first time, we demonstrate hCAP18/LL-37 in isolated human parotid and submandibular/sublingual saliva and expression of hCAP18/LL-37 in glandular intravascular neutrophils, indicating that neutrophils of the major salivary glands contribute to the LL-37 content of whole saliva.
