With three of the four women who propelled Great Britain & Northern Ireland to gold at last month's European Championships in their ranks, Europe will prove difficult to beat.
Imani Lansiquot, Bianca Williams and Dina Asher-Smith ran legs two, three and four at Berlin's Olympic Stadium en route to a 41.88 performance, the year's only sub-42 run. They'll be backed up by Ashleigh Nelson, another Briton with world and European relay medals among her credentials and compatriot Kristal Awauh, who lowered her PB to 11.16 in Berlin on Sunday.
The Americas squad could prove a formidable force, with IAAF Diamond League 200m champion Shaunae Miller-Uibo, NACAC 100m champion Jenna Prandini and Jamaican Shericka Jackson in the pool. Jackson, the NACAC 200m champion, quietly improved her career bests to 11.13 and 22.05 this season.
Asia-Pacific sends a Chinese quartet which took silver at the Asian Games last weekend in 42.84: Liang Xiaojing, Wei Yongli, Ge Manqi and Yuan Qiqi.
Bob Ramsak for the IAAF