1. Receptor Availability: Pathogens often require specific receptors on host cells to attach and enter. For example, the ACE2 receptor is crucial for SARS-CoV-2 entry into cells.
2. Cellular Environment: The intracellular environment must support pathogen replication. For instance, the low pH in lysosomes is essential for the replication of some viruses.
3. Immune Response: The host's immune response can influence tissue tropism. Some pathogens have evolved mechanisms to evade immune detection in specific tissues.
