EFFECT OF SIALODACRYOADENITIS VIRUS EXPOSURE ON ACINAR EPITHELIAL-CELLS FROM THE RAT LACRIMAL GLAND

Sialodacryoadenitis virus (SDAV), a RNA coronavirus, induces degenerat ive, necrotic and atrophic alterations in acinar epithelial cells of t he rat lacrimal gland, To begin to explore the underlying mechanism(s) of this viral effect, we sought in the present study to: (I) determin e whether SDAV invades and replicates in lacrimal gland acinar cells i n vitro, and (2) assess whether short-term SDAV challenge interferes w ith the viability or function of acinar cells in vitro, For comparison we also evaluated the relative infectivity of SDAV in acinar epitheli al cells from lacrimal, submandibular and parotid glands, given that s alivary tissues are known to be highly susceptible to SDAV infection i n vivo. Acinar epithelial cells from lacrimal, submandibular or paroti d glands were isolated from male rats, exposed briefly to SDAV or cont rol cell antigen and then cultured for four, eight or twelve days. At experimental termination, SDAV titers in both media and sonicated cell extracts were evaluated by plaque assay titration on mouse L2 cell mo nolayers, To evaluate functional aspects of lacrimal gland acinar cell s, SDAV-infected cells were incubated in the presence or absence of di hydrotestosterone and culture media were analysed by RIA to measure th e extent of the androgen-induced increase in secretory component (SC) production. Our results showed that: (I) SDAV invades and replicates i n lacrimal gland acinar cells, Viral challenge resulted in a significa nt, time-dependent increase in SDAV titers, that were primarily cell-a ssociated and greatly exceeded amounts contained in the original inocu lum; (2) SDAV infection did not compromise lacrimal acinar cell viabil ity or prevent the cellular SC response to androgens, Viral presence, though, did often attenuate the magnitude of this hormone action; and (3) SDAV infects salivary acinar cells, but the kinetics and magnitude of viral replication in lacrimal, submandibular and parotid cells sho wed considerable variations. These findings demonstrate that SDAV inva des and replicates in acinar epithelial cells from lacrimal and saliva ry glands. The resulting release of infectious propeny may play a role in the SDAV-induced pathology of exocrine tissues in vivo.