Intrinsic resistance to viral infection. Mouse macrophage restriction of herpes simplex virus replication

M Sarmiento1

  • 1Department of Veterinary Medicine and Surgery, University of Texas, Houston 77030.

Insights

Macrophages from resistant mice restrict herpes simplex virus type 1 (HSV-1) replication earlier than those from susceptible mice. This intrinsic resistance, observed in various macrophage types, correlates with in vivo resistance to lethal HSV-1 infection.

Area of Science:

  • Immunology
  • Virology
  • Genetics

Background:

  • Macrophages play a crucial role in the innate immune response to viral infections.
  • Herpes simplex virus type 1 (HSV-1) can cause severe neurological disease.
  • Genetic background influences host susceptibility to viral pathogens.

Purpose of the Study:

  • To investigate intrinsic differences in macrophage resistance to HSV-1 infection between resistant (B6) and susceptible (D2) mouse strains.
  • To determine if macrophage resistance to HSV-1 correlates with in vivo resistance to lethal infection.
  • To identify specific stages of the HSV-1 replicative cycle inhibited by macrophages.

Main Methods:

  • Isolation of macrophages from bone marrow (BM), spleen (S), peritoneal cavity (P), and thioglycolate-stimulated peritoneal (Pthio) cavities of C57BL/6 Cr (B6) and DBA/2Cr (D2) mice.
  • In vitro infection of isolated macrophages with a neurovirulent HSV-1 isolate.
  • Assessment of HSV-1 macromolecular synthesis (DNA, protein) to determine replication inhibition points.

Main Results:

  • Macrophages from resistant B6 mice consistently restricted HSV-1 macromolecular synthesis earlier in the viral cycle compared to macrophages from susceptible D2 mice.
  • B6-BM macrophages inhibited HSV-1 at two points: before alpha-protein synthesis and between gamma 1 protein and DNA synthesis.
  • Different macrophage populations (BM, P, S, Pthio) exhibited varying degrees of HSV-1 restriction, with Pthio macrophages being more permissive.

Conclusions:

  • Intrinsic macrophage resistance to HSV-1 infection is dependent on the mouse genetic background.
  • This in vitro macrophage resistance correlates with in vivo resistance to acute, lethal HSV-1 infection.
  • HSV-1 replication is inhibited at multiple stages within macrophages, with the specific inhibition points varying by macrophage source and host genetics.