diff --git a/tornado/httpserver.py b/tornado/httpserver.py
index 0f1d8e00..6c85ff38 100644
--- a/tornado/httpserver.py
+++ b/tornado/httpserver.py
@@ -318,7 +318,7 @@ class HTTPHeaders(dict):
         return dict.__getitem__(self, self._normalize_name(name))
 
     def _normalize_name(self, name):
-        return intern("-".join([w.capitalize() for w in name.split("-")]))
+        return "-".join([w.capitalize() for w in name.split("-")])
 
     @classmethod
     def parse(cls, headers_string):
diff --git a/tornado/wsgi.py b/tornado/wsgi.py
index 714b08ed..15af00f7 100644
--- a/tornado/wsgi.py
+++ b/tornado/wsgi.py
@@ -187,4 +187,4 @@ class HTTPHeaders(dict):
         return dict.__getitem__(self, self._normalize_name(name))
 
     def _normalize_name(self, name):
-        return intern("-".join([w.capitalize() for w in name.split("-")]))
+        return "-".join([w.capitalize() for w in name.split("-")])