Noninfectious L-particles supply functions which can facilitate infection by HSV-1.

The tegument of herpes simplex virus contains proteins important for the efficient initiation of infection. L-particles are noninfectious virion-related particles that lack the nucleocapsid but do contain tegument and envelope. Their ability to deliver functional proteins into cells was compared to that of virions by testing the biological activities of two tegument proteins which are present in both types of particle. Results indicated that L-particles are as efficient as virions in supplying these in a fully functional state. Thus, L-particles are biologically competent and have the potential to participate in the early stages of virus infection.