diff --git a/downloads-generation/data_mass_spec_benchmark/run_mhcflurry.py b/downloads-generation/data_mass_spec_benchmark/run_mhcflurry.py
index 37000577d752e438e48e3d2ddf742119d96a6f34..1b4253ae3b78ba151d5c8966f124a6f7888809c4 100644
--- a/downloads-generation/data_mass_spec_benchmark/run_mhcflurry.py
+++ b/downloads-generation/data_mass_spec_benchmark/run_mhcflurry.py
@@ -177,7 +177,8 @@ def run(argv=sys.argv[1:]):
             work_function=do_predictions,
             work_items=work_items,
             constant_data=GLOBAL_DATA,
-            result_serialization_method="dill",
+            input_serialization_method="dill",
+            result_serialization_method="pickle",
             clear_constant_data=True)
     else:
         worker_pool = worker_pool_with_gpu_assignments_from_args(args)