In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: Although the sP120T substitution also impaired HBsAg secretion , it did not enhance the replication of LAM - resistant clones .
### Output Text:
Although the sP120T substitution also impaired <span class="chemical">HBsAg</span> secretion , it did not enhance the replication of <span class="chemical">LAM</span> - resistant clones . 