diff --git a/sanic/response.py b/sanic/response.py
index 9e1a4437..7b7c8521 100644
--- a/sanic/response.py
+++ b/sanic/response.py
@@ -91,6 +91,7 @@ class StreamingHTTPResponse(BaseHTTPResponse):
         self.headers = Header(headers or {})
         self.chunked = chunked
         self._cookies = None
+        self.protocol = None
 
     async def write(self, data):
         """Writes a chunk of data to the streaming response.