There had been talk the 38-year-old Pacquiao might retire, but the eight-division world champion said on Wednesday his passion for the sport was still strong.
"I love this sport and until the passion is gone, I will continue to fight for God, my family, my fans and my country," Pacquiao said on his Twitter feed.
A rematch was written into the contract for the initial fight in the event Pacquiao lost and the pair are expected to face each other again later this year.
Pacquiao's defeat sparked fury among his fans, who labelled the 117-111, 115-113 and 115-113 scoring as a "hometown decision", and the Philippines Games and Amusements Board sent a letter to the WBO asking for a "thorough review" of the fight.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
On Tuesday, the WBO said five independent judges had reviewed the bout and gave the decision to Horn by seven rounds to five..
Pacquiao said in a statement to CNN Philippines late on Tuesday in reaction to the WBO's review that, in his opinion, it was clear who won.
"Let the people judge for themselves. People saw what happened," he said.
"We have seen worse judgements in the past where judges manipulated results.
"Nothing surprises me now."
(Reporting by Greg Stutchbury in Wellington; Editing by Peter Rutherford)
