diff --git a/src/wp-includes/class-http.php b/src/wp-includes/class-http.php
index d8b703bf9c..838fbe8140 100644
--- a/src/wp-includes/class-http.php
+++ b/src/wp-includes/class-http.php
@@ -21,6 +21,10 @@
 class WP_Http {
 
 	// Aliases for HTTP response codes.
+	const HTTP_CONTINUE                   = 100;
+	const SWITCHING_PROTOCOLS             = 101;
+	const PROCESSING                      = 102;
+
 	const OK                              = 200;
 	const CREATED                         = 201;
 	const ACCEPTED                        = 202;
diff --git a/tests/phpunit/tests/http/http.php b/tests/phpunit/tests/http/http.php
index 80b83f9d33..74eda29e21 100644
--- a/tests/phpunit/tests/http/http.php
+++ b/tests/phpunit/tests/http/http.php
@@ -102,4 +102,20 @@ class Tests_HTTP_HTTP extends WP_UnitTestCase {
 		  - ://example.com - assumed path in PHP >= 5.4.7, fails in <5.4.7
 		*/
 	}
+
+	/**
+	 * @ticket 35426
+	 */
+	public function test_http_response_code_constants() {
+		global $wp_header_to_desc;
+
+		$ref = new ReflectionClass( 'WP_Http' );
+		$constants = $ref->getConstants();
+
+		// This primes the `$wp_header_to_desc` global:
+		get_status_header_desc( 200 );
+
+		$this->assertEquals( array_keys( $wp_header_to_desc ), array_values( $constants ) );
+
+	}
 }